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Analyses scripts for LTTng kernel and user-space traces (official repository)

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LTTng analyses


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The LTTng analyses are a set of various executable analyses to extract and visualize monitoring data and metrics from LTTng <http://lttng.org/>_ kernel traces on the command line.

As opposed to other "live" diagnostic or monitoring solutions, this approach is based on the following workflow:

#. Record your system's activity with LTTng, a low-overhead tracer. #. Do whatever it takes for your problem to occur. #. Diagnose your problem's cause offline (when tracing is stopped).

This solution allows you to target problems that are hard to find and to "dig" until the root cause is found.

Current limitations:

  • The LTTng analyses can be quite slow to execute. There are a number of places where they could be optimized, but using the Python interpreter seems to be an important impediment.

    This project is regarded by its authors as a testing ground to experiment analysis features, user interfaces, and usability in general. It is not considered ready to analyze long traces.

Contents:

.. contents:: :local: :depth: 3 :backlinks: none

Install LTTng analyses

Required dependencies

  • Python <https://www.python.org/>_ ≥ 3.4
  • setuptools <https://pypi.python.org/pypi/setuptools>_
  • pyparsing <http://pyparsing.wikispaces.com/>_ ≥ 2.0.0
  • Babeltrace <http://diamon.org/babeltrace/>_ ≥ 1.2, < 2 with Python bindings (--enable-python-bindings when building from source)

Optional dependencies

  • LTTng <http://lttng.org/>_ ≥ 2.5: to use the lttng-analyses-record script and to trace the system in general
  • termcolor <https://pypi.python.org/pypi/termcolor/>_: color support
  • progressbar <https://pypi.python.org/pypi/progressbar/>_: terminal progress bar support (this is not required for the machine interface's progress indication feature)

Install from PyPI (online repository)

To install the latest LTTng analyses release on your system from PyPI <https://pypi.python.org/pypi/lttnganalyses>_:

#. Install the required dependencies. #. Optional: Install the optional dependencies. #. Make sure pip for Python 3 is installed on your system. The package is named python3-pip on most distributions (python-pip on Arch Linux). #. Use pip3 to install LTTng analyses:

.. code-block:: bash

  sudo pip3 install --upgrade lttnganalyses

Note that you can also install LTTng analyses locally, only for your user:

.. code-block:: bash

  pip3 install --user --upgrade lttnganalyses

Files are installed in ~/.local, therefore ~/.local/bin must be part of your PATH environment variable for the LTTng analyses to be launchable.

Install from a release tarball

To install a specific LTTng analyses release (tarball) on your system:

#. Install the required dependencies. #. Optional: Install the optional dependencies. #. Download <https://github.com/lttng/lttng-analyses/releases>_ and extract the desired release tarball. #. Use setup.py to install LTTng analyses:

.. code-block:: bash

  sudo ./setup.py install

Install from the Git repository

To install LTTng analyses from a specific branch or tag of the project's Git repository:

#. Install the required dependencies. #. Optional: Install the optional dependencies. #. Make sure pip for Python 3 is installed on your system. The package is named python3-pip on most distributions (python-pip on Arch Linux). #. Use pip3 to install LTTng analyses:

.. code-block:: bash

  sudo pip3 install --upgrade git+git://github.com/lttng/[email protected]

Replace master with the desired branch or tag name to install in the previous URL.

Note that you can also install LTTng analyses locally, only for your user:

.. code-block:: bash

  sudo pip3 install --user --upgrade git+git://github.com/lttng/[email protected]

Files are installed in ~/.local, therefore ~/.local/bin must be part of your PATH environment variable for the LTTng analyses to be launchable.

Install on Ubuntu

To install LTTng analyses on Ubuntu ≥ 12.04:

#. Add the LTTng Latest Stable PPA repository:

.. code-block:: bash

  sudo apt-get install -y software-properties-common
  sudo apt-add-repository -y ppa:lttng/ppa
  sudo apt-get update

Replace software-properties-common with python-software-properties on Ubuntu 12.04. #. Install the required dependencies:

.. code-block:: bash

  sudo apt-get install -y babeltrace
  sudo apt-get install -y python3-babeltrace
  sudo apt-get install -y python3-setuptools

On Ubuntu > 12.04:

.. code-block:: bash

  sudo apt-get install -y python3-pyparsing

On Ubuntu 12.04:

.. code-block:: bash

  sudo pip3 install --upgrade pyparsing

#. Optional: Install the optional dependencies:

.. code-block:: bash

  sudo apt-get install -y lttng-tools
  sudo apt-get install -y lttng-modules-dkms
  sudo apt-get install -y python3-progressbar
  sudo apt-get install -y python3-termcolor

#. Install LTTng analyses:

.. code-block:: bash

  sudo apt-get install -y python3-lttnganalyses

Install on Debian "sid"

To install LTTng analyses on Debian "sid":

#. Install the required dependencies:

.. code-block:: bash

  sudo apt-get install -y babeltrace
  sudo apt-get install -y python3-babeltrace
  sudo apt-get install -y python3-setuptools
  sudo apt-get install -y python3-pyparsing

#. Optional: Install the optional dependencies:

.. code-block:: bash

  sudo apt-get install -y lttng-tools
  sudo apt-get install -y lttng-modules-dkms
  sudo apt-get install -y python3-progressbar
  sudo apt-get install -y python3-termcolor

#. Install LTTng analyses:

.. code-block:: bash

  sudo apt-get install -y python3-lttnganalyses

Sample traces

If you just want to try the tools, a sample trace is available here <http://www.lttng.org/files/analysis-20150115-120942.tar.gz>_.

If you want to see a step-by-step usage of these tools to identify a single unusual request latency, you can check this blog post <https://lttng.org/blog/2015/02/04/web-request-latency-root-cause/>_, it shows how to navigate in the sample trace and accurately find the culprit.

Record a trace

This section is a quick reminder of how to record an LTTng kernel trace. See LTTng's quick start guide <http://lttng.org/docs/v2.7/#doc-getting-started>_ to familiarize with LTTng.

Automatic

LTTng analyses ships with a handy (installed) script, lttng-analyses-record, which automates the steps to record a kernel trace with the events required by the analyses.

To use lttng-analyses-record:

#. Launch the installed script:

.. code-block:: bash

  lttng-analyses-record

#. Do whatever it takes for your problem to occur. #. When you are done recording, press Ctrl+C where the script is running.

Manual

To record an LTTng kernel trace suitable for the LTTng analyses:

#. Create a tracing session:

.. code-block:: bash

  sudo lttng create

#. Create a channel with a large sub-buffer size:

.. code-block:: bash

  sudo lttng enable-channel --kernel chan --subbuf-size=8M

#. Create event rules to capture the needed events:

.. code-block:: bash

  sudo lttng enable-event --kernel --channel=chan block_bio_backmerge
  sudo lttng enable-event --kernel --channel=chan block_bio_remap
  sudo lttng enable-event --kernel --channel=chan block_rq_complete
  sudo lttng enable-event --kernel --channel=chan block_rq_issue
  sudo lttng enable-event --kernel --channel=chan irq_handler_entry
  sudo lttng enable-event --kernel --channel=chan irq_handler_exit
  sudo lttng enable-event --kernel --channel=chan irq_softirq_entry
  sudo lttng enable-event --kernel --channel=chan irq_softirq_exit
  sudo lttng enable-event --kernel --channel=chan irq_softirq_raise
  sudo lttng enable-event --kernel --channel=chan kmem_mm_page_alloc
  sudo lttng enable-event --kernel --channel=chan kmem_mm_page_free
  sudo lttng enable-event --kernel --channel=chan lttng_statedump_block_device
  sudo lttng enable-event --kernel --channel=chan lttng_statedump_file_descriptor
  sudo lttng enable-event --kernel --channel=chan lttng_statedump_process_state
  sudo lttng enable-event --kernel --channel=chan mm_page_alloc
  sudo lttng enable-event --kernel --channel=chan mm_page_free
  sudo lttng enable-event --kernel --channel=chan net_dev_xmit
  sudo lttng enable-event --kernel --channel=chan netif_receive_skb
  sudo lttng enable-event --kernel --channel=chan sched_pi_setprio
  sudo lttng enable-event --kernel --channel=chan sched_process_exec
  sudo lttng enable-event --kernel --channel=chan sched_process_fork
  sudo lttng enable-event --kernel --channel=chan sched_switch
  sudo lttng enable-event --kernel --channel=chan sched_wakeup
  sudo lttng enable-event --kernel --channel=chan sched_waking
  sudo lttng enable-event --kernel --channel=chan softirq_entry
  sudo lttng enable-event --kernel --channel=chan softirq_exit
  sudo lttng enable-event --kernel --channel=chan softirq_raise
  sudo lttng enable-event --kernel --channel=chan --syscall --all

#. Start recording:

.. code-block:: bash

  sudo lttng start

#. Do whatever it takes for your problem to occur. #. Stop recording and destroy the tracing session to free its resources:

.. code-block:: bash

  sudo lttng stop
  sudo lttng destroy

See the LTTng Documentation <http://lttng.org/docs/>_ for other use cases, like sending the trace data over the network instead of recording trace files on the target's file system.

Run an LTTng analysis

The LTTng analyses are a set of various command-line analyses. Each analysis accepts the path to a recorded trace (see Record a trace_) as its argument, as well as various command-line options to control the analysis and its output.

Many command-line options are common to all the analyses, so that you can filter by timerange, process name, process ID, minimum and maximum values, and the rest. Also note that the reported timestamps can optionally be expressed in the GMT time zone.

Each analysis is installed as an executable starting with the lttng- prefix.

.. list-table:: Available LTTng analyses :header-rows: 1

    • Command
    • Description
    • lttng-cputop
    • Per-TID, per-CPU, and total top CPU usage.
    • lttng-iolatencyfreq
    • I/O request latency distribution.
    • lttng-iolatencystats
    • Partition and system call latency statistics.
    • lttng-iolatencytop
    • Top system call latencies.
    • lttng-iolog
    • I/O operations log.
    • lttng-iousagetop
    • I/O usage top.
    • lttng-irqfreq
    • Interrupt handler duration frequency distribution.
    • lttng-irqlog
    • Interrupt log.
    • lttng-irqstats
    • Hardware and software interrupt statistics.
    • lttng-memtop
    • Per-TID top allocated/freed memory.
    • lttng-schedfreq
    • Scheduling latency frequency distribution.
    • lttng-schedlog
    • Scheduling top.
    • lttng-schedstats
    • Scheduling latency stats.
    • lttng-schedtop
    • Scheduling top.
    • lttng-periodlog
    • Period log.
    • lttng-periodstats
    • Period duration stats.
    • lttng-periodtop
    • Period duration top.
    • lttng-periodfreq
    • Period duration frequency distribution.
    • lttng-syscallstats
    • Per-TID and global system call statistics.

Use the --help option of any command to list the descriptions of the possible command-line options.

.. NOTE::

You can set the LTTNG_ANALYSES_DEBUG environment variable to 1 when you launch an analysis to enable a debug output. You can also use the general --debug option.

Filtering options

Depending on the analysis, filter options are available. The complete list of filter options is:

.. list-table:: Available filtering command-line options :header-rows: 1

    • Command-line option
    • Description
    • --begin

    • Trace time at which to begin the analysis.

      Format: HH:MM:SS[.NNNNNNNNN].

    • --cpu
    • Comma-delimited list of CPU IDs for which to display the results.
    • --end

    • Trace time at which to end the analysis.

      Format: HH:MM:SS[.NNNNNNNNN].

    • --irq
    • List of hardware IRQ numbers for which to display the results.
    • --limit
    • Maximum number of output rows per table. This option is useful for "top" analyses, like lttng-cputop.
    • --min
    • Minimum duration (µs) to keep in results.
    • --minsize
    • Minimum I/O operation size (B) to keep in results.
    • --max
    • Maximum duration (µs) to keep in results.
    • --maxsize
    • Maximum I/O operation size (B) to keep in results.
    • --procname
    • Comma-delimited list of process names for which to display the results.
    • --softirq
    • List of software IRQ numbers for which to display the results.
    • --tid
    • Comma-delimited list of thread IDs for which to display the results.

Period options

LTTng analyses feature a powerful "period engine". A period is an interval which begins and ends under specific conditions. When the analysis results are displayed, they are isolated for the periods that were opened and closed during the process.

A period can have a parent. If it's the case, then its parent needs to exist for the period to begin at all. This tree structure of periods is useful to keep a form of custom user state during the generic kernel analysis.

.. ATTENTION::

The --period and --period-captures options's arguments include characters that are considered special by most shells, like $, *, and &.

Make sure to always single-quote those arguments when running the LTTng analyses on the command line.

Period definition


You can define one or more periods on the command line, when launching
an analysis, with the ``--period`` option. This option's argument
accepts the following form (content within square brackets is optional)::

    [ NAME [ (PARENT) ] ] : BEGINEXPR [ : ENDEXPR ]

``NAME``
  Optional name of the period definition. All periods opened from this
  definition have this name.

  The syntax of this name is the same as a C identifier.

``PARENT``
  Optional name of a *previously defined* period which acts as the
  parent period definition of this definition.

  ``NAME`` must be set for ``PARENT`` to be set.

``BEGINEXPR``
  Matching expression which a given event must match in order for an
  actual period to be instantiated by this definition.

``ENDEXPR``
  Matching expression which a given event must match in order for an
  instance of this definition to be closed.

  If this part is omitted, ``BEGINEXPR`` is used for the ending
  expression too.


Matching expression
...................

A matching expression is a C-like logical expression. It supports
nesting expressions with ``(`` and ``)``, as well as the ``&&`` (logical
*AND*), ``||`` (logical *OR*), and ``!`` (logical *NOT*) operators. The
precedence of those operators is the same as in the C language.

The atomic operands in those logical expressions are comparisons. For
the following comparison syntaxes, consider that:

- ``EVT`` indicates an event source. The available event sources are:

  ``$evt``
    Current event.

  ``$begin.$evt``
    In ``BEGINEXPR``: current event (same as ``$evt``).

    In ``ENDEXPR``: event which, for this period instance, was matched
    when ``BEGINEXPR`` was evaluated.

  ``$parent.$begin.$evt``
    Event which, for the parent period instance of this period instance,
    was matched when ``BEGINEXPR`` of the parent was evaluated.
- ``FIELD`` indicates an event field source. The available event field
  sources are:

  ``NAME`` (direct field name)
    Automatic scope: try to find the field named ``NAME`` in the dynamic
    scopes in this order:

    #. Event payload
    #. Event context
    #. Event header
    #. Stream event context
    #. Packet context
    #. Packet header

  ``$payload.NAME``
    Event payload field named ``NAME``.

  ``$ctx.NAME``
    Event context field named ``NAME``.

  ``$header.NAME``
    Event header field named ``NAME``.

  ``$stream_ctx.NAME``
    Stream event context field named ``NAME``.

  ``$pkt_ctx.NAME``
    Packet context field named ``NAME``.

  ``$pkt_header.NAME``
    Packet header field named ``NAME``.
- ``VALUE`` indicates one of:

  - A constant, decimal number. This can be an integer or a real
    number, positive or negative, and supports the ``e`` scientific
    notation.

    Examples: ``23``, ``-18.28``, ``7.2e9``.
  - A double-quoted literal string. ``"`` and ``\`` can be escaped
    with ``\``.

    Examples: ``"hello, world!"``, ``"here's another \"quoted\" string"``.
  - An event field, that is, ``EVT.FIELD``, considering the replacements
    described above.

- ``NUMVALUE`` indicates one of:

  - A constant, decimal number. This can be an integer or a real
    number, positive or negative, and supports the ``e`` scientific
    notation.

    Examples: ``23``, ``-18.28``, ``7.2e9``.
  - An event field, that is, ``EVT.FIELD``, considering the replacements
    described above.

.. list-table:: Available comparison syntaxes for matching expressions
   :header-rows: 1

   * - Comparison syntax
     - Description
   * - #. ``EVT.$name == "NAME"``
       #. ``EVT.$name != "NAME"``
       #. ``EVT.$name =* "PATTERN"``
     - Name matching:

       #. Name of event source ``EVT`` is equal to ``NAME``.
       #. Name of event source ``EVT`` is not equal to ``NAME``.
       #. Name of event source ``EVT`` satisfies the globbing pattern
          ``PATTERN``
          (see `fnmatch <https://docs.python.org/3/library/fnmatch.html>`_).
   * - #. ``EVT.FIELD == VALUE``
       #. ``EVT.FIELD != VALUE``
       #. ``EVT.FIELD < NUMVALUE``
       #. ``EVT.FIELD <= NUMVALUE``
       #. ``EVT.FIELD > NUMVALUE``
       #. ``EVT.FIELD >= NUMVALUE``
       #. ``EVT.FIELD =* "PATTERN"``
     - Value matching:

       #. The value of the field ``EVT.FIELD`` is equal
          to the value ``VALUE``.
       #. The value of the field ``EVT.FIELD`` is not
          equal to the value ``VALUE``.
       #. The value of the field ``EVT.FIELD`` is lesser
          than the value ``NUMVALUE``.
       #. The value of the field ``EVT.FIELD`` is lesser
          than or equal to the value ``NUMVALUE``.
       #. The value of the field ``EVT.FIELD`` is greater
          than the value ``NUMVALUE``.
       #. The value of the field ``EVT.FIELD`` is greater
          than or equal to the value ``NUMVALUE``.
       #. The value of the field ``EVT.FIELD`` satisfies
          the globbing pattern ``PATTERN``
          (see `fnmatch <https://docs.python.org/3/library/fnmatch.html>`_).

In any case, if ``EVT.FIELD`` does not target an existing field, the
comparison including it fails. Also, string fields cannot be compared to
number values (constant or fields).


Examples
........

- Create a period instance named ``switch`` when:

  - The current event name is ``sched_switch``.

  End this period instance when:

  - The current event name is ``sched_switch``.

  Period definition::

      switch : $evt.$name == "sched_switch"

- Create a period instance named ``switch`` when:

  - The current event name is ``sched_switch`` *AND*
  - The current event's ``next_tid`` field is *NOT* equal to 0.

  End this period instance when:

  - The current event name is ``sched_switch`` *AND*
  - The current event's ``prev_tid`` field is equal to
    the ``next_tid`` field of the matched event in the begin expression *AND*
  - The current event's ``cpu_id`` field is equal to
    the ``cpu_id`` field of the matched event in the begin expression.

  Period definition::

      switch
      : $evt.$name == "sched_switch" &&
        $evt.next_tid != 0
      : $evt.$name == "sched_switch" &&
        $evt.prev_tid == $begin.$evt.next_tid &&
        $evt.cpu_id == $begin.$evt.cpu_id

- Create a period instance named ``irq`` when:

  - A parent period instance named ``switch`` is currently opened.
  - The current event name satisfies the ``irq_*_entry`` globbing
    pattern *AND*
  - The current event's ``cpu_id`` field is equal to the ``cpu_id``
    field of the matched event in the begin expression of the parent
    period instance.

  End this period instance when:

  - The current event name is ``irq_handler_exit`` *AND*
  - The current event's ``cpu_id`` field is equal to
    the ``cpu_id`` field of the matched event in the begin expression.

  Period definition::

      irq(switch)
      : $evt.$name =* "irq_*_entry" &&
        $evt.cpu_id == $parent.$begin.$evt.cpu_id
      : $evt.$name == "irq_handler_exit" &&
        $evt.cpu_id == $begin.$evt.cpu_id

- Create a period instance named ``hello`` when:

  - The current event name satisfies the ``hello*`` globbing pattern,
    but excludes ``hello world``.

  End this period instance when:

  - The current event name is the same as the name of the matched event
    in the begin expression *AND*
  - The current event's ``theid`` header field is lesser than or equal
    to 231.

  Period definition::

      hello
      : $evt.$name =* "hello*" &&
        $evt.$name != "hello world"
      : $evt.$name == $begin.$evt.$name &&
        $evt.$header.theid <= 231


Period captures
~~~~~~~~~~~~~~~

When a period instance begins or ends, the analysis can capture the
current values of specific event fields and display them in its
results.

You can set period captures with the ``--period-captures`` command-line
option. This option's argument accepts the following form
(content within square brackets is optional)::

    NAME : BEGINCAPTURES [ : ENDCAPTURES ]

``NAME``
  Name of period instances on which to apply those captures.

  A ``--period`` option in the same command line must define this name.

``BEGINCAPTURES``
  Comma-delimited list of event fields to capture when the beginning
  expression of the period definition named ``NAME`` is matched.

``ENDCAPTURES``
  Comma-delimited list of event fields to capture when the ending
  expression of the period definition named ``NAME`` is matched.

  If this part is omitted, there are no end captures.

The format of ``BEGINCAPTURES`` and ``ENDCAPTURES`` is a comma-delimited
list of tokens having this format::

    [ CAPTURENAME = ] EVT.FIELD

or::

    [ CAPTURENAME = ] EVT.$name

``CAPTURENAME``
  Custom name for this capture. The syntax of this name is the same as
  a C identifier.

  If this part is omitted, the literal expression used for ``EVT.FIELD``
  is used.

``EVT`` and ``FIELD``
  See `Matching expression`_.


Period select and aggregate parameters

With lttng-periodlog, it is possible to see the list of periods in the context of their parent. By specifying the --aggregate-by, the lines in the log present on the same line the timerange of the period specified by the --select argument at the timerange of the parent period that contains it. In lttng-periodstats and lttng-periodfreq, these two flags are used as filter to limit the output to only the relevant periods. If omitted, all existing combinations of parent/child statistics and frequency distributions are output.

Grouping


When fields are captured during the period analyses, it is possible to compute
the statistics and frequency distribution grouped by values of the these
fields, instead of globally for the trace. The format is::

    --group-by "PERIODNAME.CAPTURENAME[, PERIODNAME.CAPTURENAME]"

If multiple values are passed, the analysis outputs one list of tables
(statistics and/or frequency distribution) for each unique combination of the
field's values.

For example, if we track the ``open`` system call and we are interested in the
average duration of this call by filename, we only have to capture the filename
field and group the results by ``open.filename``.


Examples
........

Begin captures only::

    switch
    : $evt.next_tid,
      name = $evt.$name,
      msg_id = $parent.$begin.$evt.id

Begin and end captures::

    hello
    : beginning = $evt.$ctx.begin_ts,
      $evt.received_bytes
    : $evt.send_bytes,
      $evt.$name,
      begin = $begin.$evt.$ctx.begin_ts
      end = $evt.$ctx.end_ts

Top scheduling latency (delay between ``sched_waking(tid=$TID)`` and ``sched_switch(next_tid=$TID)``)
with recording of the procname of the waker (dependant of the ``procname`` context in the trace),
priority and target CPU:

.. code-block:: bash

   lttng-periodtop /path/to/trace \
       --period 'wake : $evt.$name == "sched_waking" : $evt.$name == "sched_switch" && $evt.next_tid == $begin.$evt.$payload.tid' \
       --period-capture 'wake : waker = $evt.procname, prio = $evt.prio : wakee = $evt.next_comm, cpu = $evt.cpu_id'

::

    Timerange: [2016-07-21 17:07:47.832234248, 2016-07-21 17:07:48.948152659]
    Period top
    Begin                End                   Duration (us) Name            Begin capture                       End capture
    [17:07:47.835338581, 17:07:47.946834976]      111496.395 wake            waker = lttng-consumerd             wakee = kworker/0:2
                                                                             prio = 20                           cpu = 0
    [17:07:47.850409057, 17:07:47.946829256]       96420.199 wake            waker = swapper/2                   wakee = migration/0
                                                                             prio = -100                         cpu = 0
    [17:07:48.300313282, 17:07:48.300993892]         680.610 wake            waker = Xorg                        wakee = ibus-ui-gtk3
                                                                             prio = 20                           cpu = 3
    [17:07:48.300330060, 17:07:48.300920648]         590.588 wake            waker = Xorg                        wakee = ibus-x11
                                                                             prio = 20                           cpu = 3


Log of all the IRQ handled while a user-space process was running, capture the procname of the process interrupted, the name and number of the IRQ:

.. code-block:: bash

    lttng-periodlog /path/to/trace \
        --period 'switch : $evt.$name == "sched_switch" && $evt.next_tid != 0 : $evt.$name == "sched_switch" && $evt.prev_tid == $begin.$evt.next_tid && $evt.cpu_id == $begin.$evt.cpu_id' \
        --period 'irq(switch) : $evt.$name == "irq_handler_entry" && $evt.cpu_id == $parent.$begin.$evt.cpu_id : $evt.$name == "irq_handler_exit" && $evt.cpu_id == $begin.$evt.cpu_id' \
        --period-capture 'irq : name = $evt.name, irq = $evt.irq, current = $parent.$begin.$evt.next_comm'

::

    Period log
    Begin                End                   Duration (us) Name            Begin capture                       End capture
    [10:58:26.169238875, 10:58:26.169244920]           6.045 switch
    [10:58:26.169598385, 10:58:26.169602967]           4.582 irq             name = ahci
                                                                             irq = 41
                                                                             current = lttng-consumerd
    [10:58:26.169811553, 10:58:26.169816218]           4.665 irq             name = ahci
                                                                             irq = 41
                                                                             current = lttng-consumerd
    [10:58:26.170025600, 10:58:26.170030197]           4.597 irq             name = ahci
                                                                             irq = 41
                                                                             current = lttng-consumerd
    [10:58:26.169236842, 10:58:26.170105711]         868.869 switch


Log of all the ``open`` system call periods aggregated by the ``sched_switch`` in which they occurred:

.. code-block:: bash

    lttng-periodlog /path/to/trace \
        --period 'switch : $evt.$name == "sched_switch" : $evt.$name == "sched_switch" && $begin.$evt.next_tid == $evt.prev_tid && $begin.$evt.cpu_id == $evt.cpu_id' \
        --period 'open(switch) : $evt.$name == "syscall_entry_open" && $parent.$begin.$evt.cpu_id == $evt.cpu_id : $evt.$name == "syscall_exit_open" && $begin.$evt.cpu_id == $evt.cpu_id' \
        --period-captures 'switch : comm = $evt.next_comm, cpu = $evt.cpu_id, tid = $evt.next_tid' \
        --period-captures 'open : filename = $evt.filename : fd = $evt.ret' \
        --select open
        --aggregate-by switch

::

    Aggregated log
    Aggregation of (open) by switch
                                        Parent                                  |                                     |                           Durations (us)                        |
    Begin                End                      Duration (us) Name            | Child name                    Count |        Min          Avg          Max         Stdev      Runtime | Parent captures
    [10:58:26.222823677, 10:58:26.224039381]           1215.704 switch          | switch/open                       3 |      7.517        9.548       11.248        1.887        28.644 | switch.comm = bash, switch.cpu = 3, switch.tid = 12420
    [10:58:26.856224058, 10:58:26.856589867]            365.809 switch          | switch/open                       1 |     77.620       77.620       77.620            ?        77.620 | switch.comm = ntpd, switch.cpu = 0, switch.tid = 11132
    [10:58:27.000068031, 10:58:27.000954859]            886.828 switch          | switch/open                      15 |      9.224       16.126       37.190        6.681       241.894 | switch.comm = irqbalance, switch.cpu = 0, switch.tid = 1656
    [10:58:27.225474282, 10:58:27.229160014]           3685.732 switch          | switch/open                      22 |      5.797        6.767        9.308        0.972       148.881 | switch.comm = bash, switch.cpu = 1, switch.tid = 12421


Statistics about the memory allocation performed within an ``open`` system call
within a single ``sched_switch`` (no blocking or preemption):

.. code-block:: bash

    lttng-periodstats /path/to/trace \
        --period 'switch : $evt.$name == "sched_switch" : $evt.$name == "sched_switch" && $begin.$evt.next_tid == $evt.prev_tid && $begin.$evt.cpu_id == $evt.cpu_id' \
        --period 'open(switch) : $evt.$name == "syscall_entry_open" && $parent.$begin.$evt.cpu_id == $evt.cpu_id : $evt.$name == "syscall_exit_open" && $begin.$evt.cpu_id == $evt.cpu_id' \
        --period 'alloc(open) : $evt.$name == "kmem_cache_alloc" && $parent.$begin.$evt.cpu_id == $evt.cpu_id : $evt.$name == "kmem_cache_free" && $evt.ptr == $begin.$evt.ptr' \
        --period-captures 'switch : comm = $evt.next_comm, cpu = $evt.cpu_id, tid = $evt.next_tid' \
        --period-captures 'open : filename = $evt.filename : fd = $evt.ret' \
        --period-captures 'alloc : ptr = $evt.ptr'

::

   Timerange: [2015-01-06 10:58:26.140545481, 2015-01-06 10:58:27.229358936]
   Period tree:
   switch
   |-- open
       |-- alloc

   Period statistics (us)
   Period                       Count           Min           Avg           Max         Stdev      Runtime
   switch                         831         2.824      5233.363    172056.802     16197.531  4348924.614
   switch/open                     41         5.797        12.123        77.620        12.076      497.039
   switch/open/alloc               44         1.152        10.277        74.476        11.582      452.175

   Per-parent period duration statistics (us)
   With active children
   Period                    Parent                              Min           Avg           Max         Stdev
   switch/open               switch                           28.644       124.260       241.894        92.667
   switch/open/alloc         switch                           24.036       113.044       229.713        87.827
   switch/open/alloc         switch/open                       4.550        11.029        74.476        11.768

   Per-parent duration ratio (%)
   With active children
   Period                    Parent                              Min           Avg           Max         Stdev
   switch/open               switch                                2        13.723            27        12.421
   switch/open/alloc         switch                                1        12.901            25        12.041
   switch/open/alloc         switch/open                          76        88.146           115         7.529

   Per-parent period count statistics
   With active children
   Period                    Parent                              Min           Avg           Max         Stdev
   switch/open               switch                                1        10.250            22         9.979
   switch/open/alloc         switch                                1        11.000            22        10.551
   switch/open/alloc         switch/open                           1         1.073             2         0.264

   Per-parent period duration statistics (us)
   Globally
   Period                    Parent                              Min           Avg           Max         Stdev
   switch/open               switch                            0.000         0.598       241.894        10.251
   switch/open/alloc         switch                            0.000         0.544       229.713         9.443
   switch/open/alloc         switch/open                       4.550        11.029        74.476        11.768

   Per-parent duration ratio (%)
   Globally
   Period                    Parent                              Min           Avg           Max         Stdev
   switch/open               switch                                0         0.066            27         1.209
   switch/open/alloc         switch                                0         0.062            25         1.150
   switch/open/alloc         switch/open                          76        88.146           115         7.529

   Per-parent period count statistics
   Globally
   Period                    Parent                              Min           Avg           Max         Stdev
   switch/open               switch                                0         0.049            22         0.929
   switch/open/alloc         switch                                0         0.053            22         0.991
   switch/open/alloc         switch/open                           1         1.073             2         0.264


These statistics can also be scoped by value of the FD returned by the ``open``
system, by appending ``--group-by "open.fd"`` to the previous command line.
That way previous tables will be output for each value of FD returned, so it
is possible to observe the behaviour based on the parameters of a system call.

Using the ``lttng-periodfreq`` or the ``--freq`` parameter, these tables can
also be presented as frequency distributions.


Progress options
----------------

If the `progressbar <https://pypi.python.org/pypi/progressbar/>`_
optional dependency is installed, a progress bar is available to
indicate the progress of the analysis.

By default, the progress bar is based on the current event's timestamp.

Progress options are:

.. list-table:: Available progress command-line options
   :header-rows: 1

   * - Command-line option
     - Description
   * - ``--no-progress``
     - Disable the progress bar.
   * - ``--progress-use-size``
     - Use the approximate event size instead of the current event's
       timestamp to estimate the progress value.


Machine interface
-----------------

If you want to display LTTng analyses results in a custom viewer,
you can use the JSON-based LTTng analyses machine interface (LAMI).
Each command in the previous table has its corresponding LAMI version
with the ``-mi`` suffix. For example, the LAMI version of
``lttng-cputop`` is ``lttng-cputop-mi``.

This version of LTTng analyses conforms to
`LAMI 1.0 <http://lttng.org/files/lami/lami-1.0.1.html>`_.

The LAMI output can be used in TraceCompass (>=2.1) to create graphs based
on the output of the scripts.



Examples
========

This section shows a few examples of using some LTTng analyses.

I/O
---

Partition and system call latency statistics

.. code-block:: bash

lttng-iolatencystats /path/to/trace

::

Timerange: [2015-01-06 10:58:26.140545481, 2015-01-06 10:58:27.229358936]
Syscalls latency statistics (usec):
Type                    Count            Min        Average            Max          Stdev
-----------------------------------------------------------------------------------------
Open                       45          5.562         13.835         77.683         15.263
Read                      109          0.316          5.774         62.569          9.277
Write                     101          0.256          7.060         48.531          8.555
Sync                      207         19.384         40.664        160.188         21.201

Disk latency statistics (usec):
Name                    Count            Min        Average            Max          Stdev
-----------------------------------------------------------------------------------------
dm-0                      108          0.001          0.004          0.007          1.306

I/O request latency distribution


.. code-block:: bash

   lttng-iolatencyfreq /path/to/trace

::

    Timerange: [2015-01-06 10:58:26.140545481, 2015-01-06 10:58:27.229358936]
    Open latency distribution (usec)
    ###############################################################################
     5.562 ███████████████████████████████████████████████████████████████████  25
     9.168 ██████████                                                            4
    12.774 █████████████████████                                                 8
    16.380 ████████                                                              3
    19.986 █████                                                                 2
    23.592                                                                       0
    27.198                                                                       0
    30.804                                                                       0
    34.410 ██                                                                    1
    38.016                                                                       0
    41.623                                                                       0
    45.229                                                                       0
    48.835                                                                       0
    52.441                                                                       0
    56.047                                                                       0
    59.653                                                                       0
    63.259                                                                       0
    66.865                                                                       0
    70.471                                                                       0
    74.077 █████                                                                 2


Top system call latencies
~~~~~~~~~~~~~~~~~~~~~~~~~

.. code-block:: bash

   lttng-iolatencytop /path/to/trace --limit=3 --minsize=2

::

    Checking the trace for lost events...
    Timerange: [2015-01-15 12:18:37.216484041, 2015-01-15 12:18:53.821580313]
    Top open syscall latencies (usec)
    Begin               End                  Name             Duration (usec)         Size  Proc                     PID      Filename
    [12:18:50.432950815,12:18:50.870648568]  open                  437697.753          N/A  apache2                  31517    /var/lib/php5/sess_0ifir2hangm8ggaljdphl9o5b5 (fd=13)
    [12:18:52.946080165,12:18:52.946132278]  open                      52.113          N/A  apache2                  31588    /var/lib/php5/sess_mr9045p1k55vin1h0vg7rhgd63 (fd=13)
    [12:18:46.800846035,12:18:46.800874916]  open                      28.881          N/A  apache2                  31591    /var/lib/php5/sess_r7c12pccfvjtas15g3j69u14h0 (fd=13)
    [12:18:51.389797604,12:18:51.389824426]  open                      26.822          N/A  apache2                  31520    /var/lib/php5/sess_4sdb1rtjkhb78sabnoj8gpbl00 (fd=13)

    Top read syscall latencies (usec)
    Begin               End                  Name             Duration (usec)         Size  Proc                     PID      Filename
    [12:18:37.256073107,12:18:37.256555967]  read                     482.860       7.00 B  bash                     10237    unknown (origin not found) (fd=3)
    [12:18:52.000209798,12:18:52.000252304]  read                      42.506      1.00 KB  irqbalance               1337     /proc/interrupts (fd=3)
    [12:18:37.256559439,12:18:37.256601615]  read                      42.176       5.00 B  bash                     10237    unknown (origin not found) (fd=3)
    [12:18:42.000281918,12:18:42.000320016]  read                      38.098      1.00 KB  irqbalance               1337     /proc/interrupts (fd=3)

    Top write syscall latencies (usec)
    Begin               End                  Name             Duration (usec)         Size  Proc                     PID      Filename
    [12:18:49.913241516,12:18:49.915908862]  write                   2667.346      95.00 B  apache2                  31584    /var/log/apache2/access.log (fd=8)
    [12:18:37.472823631,12:18:37.472859836]  writev                    36.205     21.97 KB  apache2                  31544    unknown (origin not found) (fd=12)
    [12:18:37.991578372,12:18:37.991612724]  writev                    34.352     21.97 KB  apache2                  31589    unknown (origin not found) (fd=12)
    [12:18:39.547778549,12:18:39.547812515]  writev                    33.966     21.97 KB  apache2                  31584    unknown (origin not found) (fd=12)

    Top sync syscall latencies (usec)
    Begin               End                  Name             Duration (usec)         Size  Proc                     PID      Filename
    [12:18:50.162776739,12:18:51.157522361]  sync                  994745.622          N/A  sync                     22791    None (fd=None)
    [12:18:37.227867532,12:18:37.232289687]  sync_file_range         4422.155          N/A  lttng-consumerd          19964    /home/julien/lttng-traces/analysis-20150115-120942/kernel/metadata (fd=32)
    [12:18:37.238076585,12:18:37.239012027]  sync_file_range          935.442          N/A  lttng-consumerd          19964    /home/julien/lttng-traces/analysis-20150115-120942/kernel/metadata (fd=32)
    [12:18:37.220974711,12:18:37.221647124]  sync_file_range          672.413          N/A  lttng-consumerd          19964    /home/julien/lttng-traces/analysis-20150115-120942/kernel/metadata (fd=32)


I/O operations log
~~~~~~~~~~~~~~~~~~

.. code-block:: bash

   lttng-iolog /path/to/trace

::

    [10:58:26.221618530,10:58:26.221620659]  write                      2.129       8.00 B  /usr/bin/x-term          11793    anon_inode:[eventfd] (fd=5)
    [10:58:26.221623609,10:58:26.221628055]  read                       4.446      50.00 B  /usr/bin/x-term          11793    /dev/ptmx (fd=24)
    [10:58:26.221638929,10:58:26.221640008]  write                      1.079       8.00 B  /usr/bin/x-term          11793    anon_inode:[eventfd] (fd=5)
    [10:58:26.221676232,10:58:26.221677385]  read                       1.153       8.00 B  /usr/bin/x-term          11793    anon_inode:[eventfd] (fd=5)
    [10:58:26.223401804,10:58:26.223411683]  open                       9.879          N/A  sleep                    12420    /etc/ld.so.cache (fd=3)
    [10:58:26.223448060,10:58:26.223455577]  open                       7.517          N/A  sleep                    12420    /lib/x86_64-linux-gnu/libc.so.6 (fd=3)
    [10:58:26.223456522,10:58:26.223458898]  read                       2.376     832.00 B  sleep                    12420    /lib/x86_64-linux-gnu/libc.so.6 (fd=3)
    [10:58:26.223918068,10:58:26.223929316]  open                      11.248          N/A  sleep                    12420     (fd=3)
    [10:58:26.231881565,10:58:26.231895970]  writev                    14.405      16.00 B  /usr/bin/x-term          11793    socket:[45650] (fd=4)
    [10:58:26.231979636,10:58:26.231988446]  recvmsg                    8.810      16.00 B  Xorg                     1827     socket:[47480] (fd=38)


I/O usage top
~~~~~~~~~~~~~

.. code-block:: bash

   lttng-iousagetop /path/to/trace

::

    Timerange: [2014-10-07 16:36:00.733214969, 2014-10-07 16:36:18.804584183]
    Per-process I/O Read
    ###############################################################################
    ██████████████████████████████████████████████████    16.00 MB lttng-consumerd (2619)         0 B  file   4.00 B  net  16.00 MB unknown
    █████                                                  1.72 MB lttng-consumerd (2619)         0 B  file      0 B  net   1.72 MB unknown
    █                                                    398.13 KB postgres (4219)           121.05 KB file 277.07 KB net   8.00 B  unknown
                                                         256.09 KB postgres (1348)                0 B  file 255.97 KB net 117.00 B  unknown
                                                         204.81 KB postgres (4218)           204.81 KB file      0 B  net      0 B  unknown
                                                         123.77 KB postgres (4220)           117.50 KB file   6.26 KB net   8.00 B  unknown
    Per-process I/O Write
    ###############################################################################
    ██████████████████████████████████████████████████    16.00 MB lttng-consumerd (2619)         0 B  file   8.00 MB net   8.00 MB unknown
    ██████                                                 2.20 MB postgres (4219)             2.00 MB file 202.23 KB net      0 B  unknown
    █████                                                  1.73 MB lttng-consumerd (2619)         0 B  file 887.73 KB net 882.58 KB unknown
    ██                                                   726.33 KB postgres (1165)             8.00 KB file   6.33 KB net 712.00 KB unknown
                                                         158.69 KB postgres (1168)           158.69 KB file      0 B  net      0 B  unknown
                                                          80.66 KB postgres (1348)                0 B  file  80.66 KB net      0 B  unknown
    Files Read
    ###############################################################################
    ██████████████████████████████████████████████████     8.00 MB anon_inode:[lttng_stream] (lttng-consumerd) 'fd 32 in lttng-consumerd (2619)'
    █████                                                834.41 KB base/16384/pg_internal.init 'fd 7 in postgres (4219)', 'fd 7 in postgres (4220)', 'fd 7 in postgres (4221)', 'fd 7 in postgres (4222)', 'fd 7 in postgres (4223)', 'fd 7 in postgres (4224)', 'fd 7 in postgres (4225)', 'fd 7 in postgres (4226)'
    █                                                    256.09 KB socket:[8893] (postgres) 'fd 9 in postgres (1348)'
    █                                                    174.69 KB pg_stat_tmp/pgstat.stat 'fd 9 in postgres (4218)', 'fd 9 in postgres (1167)'
                                                         109.48 KB global/pg_internal.init 'fd 7 in postgres (4218)', 'fd 7 in postgres (4219)', 'fd 7 in postgres (4220)', 'fd 7 in postgres (4221)', 'fd 7 in postgres (4222)', 'fd 7 in postgres (4223)', 'fd 7 in postgres (4224)', 'fd 7 in postgres (4225)', 'fd 7 in postgres (4226)'
                                                         104.30 KB base/11951/pg_internal.init 'fd 7 in postgres (4218)'
                                                          12.85 KB socket (lttng-sessiond) 'fd 30 in lttng-sessiond (384)'
                                                           4.50 KB global/pg_filenode.map 'fd 7 in postgres (4218)', 'fd 7 in postgres (4219)', 'fd 7 in postgres (4220)', 'fd 7 in postgres (4221)', 'fd 7 in postgres (4222)', 'fd 7 in postgres (4223)', 'fd 7 in postgres (4224)', 'fd 7 in postgres (4225)', 'fd 7 in postgres (4226)'
                                                           4.16 KB socket (postgres) 'fd 9 in postgres (4226)'
                                                           4.00 KB /proc/interrupts 'fd 3 in irqbalance (1104)'
    Files Write
    ###############################################################################
    ██████████████████████████████████████████████████     8.00 MB socket:[56371] (lttng-consumerd) 'fd 30 in lttng-consumerd (2619)'
    █████████████████████████████████████████████████      8.00 MB pipe:[53306] (lttng-consumerd) 'fd 12 in lttng-consumerd (2619)'
    ██████████                                             1.76 MB pg_xlog/00000001000000000000000B 'fd 31 in postgres (4219)'
    █████                                                887.82 KB socket:[56369] (lttng-consumerd) 'fd 26 in lttng-consumerd (2619)'
    █████                                                882.58 KB pipe:[53309] (lttng-consumerd) 'fd 18 in lttng-consumerd (2619)'
                                                         160.00 KB /var/lib/postgresql/9.1/main/base/16384/16602 'fd 14 in postgres (1165)'
                                                         158.69 KB pg_stat_tmp/pgstat.tmp 'fd 3 in postgres (1168)'
                                                         144.00 KB /var/lib/postgresql/9.1/main/base/16384/16613 'fd 12 in postgres (1165)'
                                                          88.00 KB /var/lib/postgresql/9.1/main/base/16384/16609 'fd 11 in postgres (1165)'
                                                          78.28 KB socket:[8893] (postgres) 'fd 9 in postgres (1348)'
    Block I/O Read
    ###############################################################################
    Block I/O Write
    ###############################################################################
    ██████████████████████████████████████████████████     1.76 MB postgres (pid=4219)
    ████                                                 160.00 KB postgres (pid=1168)
    ██                                                   100.00 KB kworker/u8:0 (pid=1540)
    ██                                                    96.00 KB jbd2/vda1-8 (pid=257)
    █                                                     40.00 KB postgres (pid=1166)
                                                           8.00 KB kworker/u9:0 (pid=4197)
                                                           4.00 KB kworker/u9:2 (pid=1381)
    Disk nr_sector
    ###############################################################################
    ███████████████████████████████████████████████████████████████████  4416.00 sectors  vda1
    Disk nr_requests
    ###############################################################################
    ████████████████████████████████████████████████████████████████████  177.00 requests  vda1
    Disk request time/sector
    ###############################################################################
    ██████████████████████████████████████████████████████████████████   0.01 ms  vda1
    Network recv_bytes
    ###############################################################################
    ███████████████████████████████████████████████████████  739.50 KB eth0
    █████                                                    80.27 KB lo
    Network sent_bytes
    ###############################################################################
    ████████████████████████████████████████████████████████  9.36 MB eth0


System calls
--------

Per-TID and global system call statistics

.. code-block:: bash

lttng-syscallstats /path/to/trace

::

Timerange: [2015-01-15 12:18:37.216484041, 2015-01-15 12:18:53.821580313]
Per-TID syscalls statistics (usec)
find (22785)                          Count            Min        Average          Max      Stdev  Return values
 - getdents                           14240          0.380        364.301    43372.450   1629.390  {'success': 14240}
 - close                              14236          0.233          0.506        4.932      0.217  {'success': 14236}
 - fchdir                             14231          0.252          0.407        5.769      0.117  {'success': 14231}
 - open                                7123          0.779          2.321       12.697      0.936  {'success': 7119, 'ENOENT': 4}
 - newfstatat                          7118          1.457        143.562    28103.532   1410.281  {'success': 7118}
 - openat                              7118          1.525          2.411        9.107      0.771  {'success': 7118}
 - newfstat                            7117          0.272          0.654        8.707      0.248  {'success': 7117}
 - write                                573          0.298          0.715        8.584      0.391  {'success': 573}
 - brk                                   27          0.615          5.768       30.792      7.830  {'success': 27}
 - rt_sigaction                          22          0.227          0.283        0.589      0.098  {'success': 22}
 - mmap                                  12          1.116          2.116        3.597      0.762  {'success': 12}
 - mprotect                               6          1.185          2.235        3.923      1.148  {'success': 6}
 - read                                   5          0.925          2.101        6.300      2.351  {'success': 5}
 - ioctl                                  4          0.342          1.151        2.280      0.873  {'success': 2, 'ENOTTY': 2}
 - access                                 4          1.166          2.530        4.202      1.527  {'ENOENT': 4}
 - rt_sigprocmask                         3          0.325          0.570        0.979      0.357  {'success': 3}
 - dup2                                   2          0.250          0.562        0.874          ?  {'success': 2}
 - munmap                                 2          3.006          5.399        7.792          ?  {'success': 2}
 - execve                                 1       7277.974       7277.974     7277.974          ?  {'success': 1}
 - setpgid                                1          0.945          0.945        0.945          ?  {'success': 1}
 - fcntl                                  1              ?          0.000        0.000          ?  {}
 - newuname                               1          1.240          1.240        1.240          ?  {'success': 1}
Total:                                71847
-----------------------------------------------------------------------------------------------------------------
apache2 (31517)                       Count            Min        Average          Max      Stdev  Return values
 - fcntl                                192              ?          0.000        0.000          ?  {}
 - newfstat                             156          0.237          0.484        1.102      0.222  {'success': 156}
 - read                                 144          0.307          1.602       16.307      1.698  {'success': 117, 'EAGAIN': 27}
 - access                                96          0.705          1.580        3.364      0.670  {'success': 12, 'ENOENT': 84}
 - newlstat                              84          0.459          0.738        1.456      0.186  {'success': 63, 'ENOENT': 21}
 - newstat                               74          0.735          2.266       11.212      1.772  {'success': 50, 'ENOENT': 24}
 - lseek                                 72          0.317          0.522        0.915      0.112  {'success': 72}
 - close                                 39          0.471          0.615        0.867      0.069  {'success': 39}
 - open                                  36          2.219      12162.689   437697.753  72948.868  {'success': 36}
 - getcwd                                28          0.287          0.701        1.331      0.277  {'success': 28}
 - poll                                  27          1.080       1139.669     2851.163    856.723  {'success': 27}
 - times                                 24          0.765          0.956        1.327      0.107  {'success': 24}
 - setitimer                             24          0.499          5.848       16.668      4.041  {'success': 24}
 - write                                 24          5.467          6.784       16.827      2.459  {'success': 24}
 - writev                                24         10.241         17.645       29.817      5.116  {'success': 24}
 - mmap                                  15          3.060          3.482        4.406      0.317  {'success': 15}
 - munmap                                15          2.944          3.502        4.154      0.427  {'success': 15}
 - brk                                   12          0.738          4.579       13.795      4.437  {'success': 12}
 - chdir                                 12          0.989          1.600        2.353      0.385  {'success': 12}
 - flock                                  6          0.906          1.282        2.043      0.423  {'success': 6}
 - rt_sigaction                           6          0.530          0.725        1.123      0.217  {'success': 6}
 - pwrite64                               6          1.262          1.430        1.692      0.143  {'success': 6}
 - rt_sigprocmask                         6          0.539          0.650        0.976      0.162  {'success': 6}
 - shutdown                               3          7.323          8.487       10.281      1.576  {'success': 3}
 - getsockname                            3          1.015          1.228        1.585      0.311  {'success': 3}
 - accept4                                3    5174453.611    3450157.282  5176018.235          ?  {'success': 2}
Total:                                 1131

Interrupts

Hardware and software interrupt statistics


.. code-block:: bash

   lttng-irqstats /path/to/trace

::

    Timerange: [2014-03-11 16:05:41.314824752, 2014-03-11 16:05:45.041994298]
    Hard IRQ                                             Duration (us)
                           count          min          avg          max        stdev
    ----------------------------------------------------------------------------------|
    1:  <i8042>               30       10.901       45.500       64.510       18.447  |
    42: <ahci>               259        3.203        7.863       21.426        3.183  |
    43: <eth0>                 2        3.859        3.976        4.093        0.165  |
    44: <iwlwifi>             92        0.300        3.995        6.542        2.181  |

    Soft IRQ                                             Duration (us)                                        Raise latency (us)
                           count          min          avg          max        stdev  |  count          min          avg          max        stdev
    ----------------------------------------------------------------------------------|------------------------------------------------------------
    1:  <TIMER_SOFTIRQ>      495        0.202       21.058       51.060       11.047  |     53        2.141       11.217       20.005        7.233
    3:  <NET_RX_SOFTIRQ>      14        0.133        9.177       32.774       10.483  |     14        0.763        3.703       10.902        3.448
    4:  <BLOCK_SOFTIRQ>      257        5.981       29.064      125.862       15.891  |    257        0.891        3.104       15.054        2.046
    6:  <TASKLET_SOFTIRQ>     26        0.309        1.198        1.748        0.329  |     26        9.636       39.222       51.430       11.246
    7:  <SCHED_SOFTIRQ>      299        1.185       14.768       90.465       15.992  |    298        1.286       31.387       61.700       11.866
    9:  <RCU_SOFTIRQ>        338        0.592        3.387       13.745        1.356  |    147        2.480       29.299       64.453       14.286


Interrupt handler duration frequency distribution

.. code-block:: bash

lttng-irqfreq --timerange=[16:05:42,16:05:45] --irq=44 --stats /path/to/trace

::

Timerange: [2014-03-11 16:05:42.042034570, 2014-03-11 16:05:44.998914297]
Hard IRQ                                             Duration (us)
                       count          min          avg          max        stdev
----------------------------------------------------------------------------------|
44: <iwlwifi>             72        0.300        4.018        6.542        2.164  |
Frequency distribution iwlwifi (44)
###############################################################################
0.300 █████                                                                 1.00
0.612 ██████████████████████████████████████████████████████████████        12.00
0.924 ████████████████████                                                  4.00
1.236 ██████████                                                            2.00
1.548                                                                       0.00
1.861 █████                                                                 1.00
2.173                                                                       0.00
2.485 █████                                                                 1.00
2.797 ██████████████████████████                                            5.00
3.109 █████                                                                 1.00
3.421 ███████████████                                                       3.00
3.733                                                                       0.00
4.045 █████                                                                 1.00
4.357 █████                                                                 1.00
4.669 ██████████                                                            2.00
4.981 ██████████                                                            2.00
5.294 █████████████████████████████████████████                             8.00
5.606 ████████████████████████████████████████████████████████████████████  13.00
5.918 ██████████████████████████████████████████████████████████████        12.00
6.230 ███████████████                                                       3.00

Community

LTTng analyses is part of the LTTng <http://lttng.org/>_ project and shares its community.

We hope you have fun trying this project and please remember it is a work in progress; feedback, bug reports and improvement ideas are always welcome!

.. list-table:: LTTng analyses project's communication channels :header-rows: 1

    • Item
    • Location
    • Notes
    • Mailing list
    • lttng-dev <https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev>_ ([email protected])
    • Preferably, use the [lttng-analyses] subject prefix
    • IRC
    • #lttng on the OFTC network
    • Code contribution
    • Create a new GitHub pull request <https://github.com/lttng/lttng-analyses/pulls>_
    • Bug reporting
    • Create a new GitHub issue <https://github.com/lttng/lttng-analyses/issues/new>_
    • Continuous integration
    • lttng-analyses_master_build item <https://ci.lttng.org/job/lttng-analyses_master_build/>_ on LTTng's CI and lttng/lttng-analyses project <https://travis-ci.org/lttng/lttng-analyses>_ on Travis CI
    • Blog
    • The LTTng blog <http://lttng.org/blog/>_ contains some posts about LTTng analyses
Note that the project description data, including the texts, logos, images, and/or trademarks, for each open source project belongs to its rightful owner. If you wish to add or remove any projects, please contact us at [email protected].