LIBMSR
Welcome to Libmsr, a friendly (well, friendlier) interface to many of the model-specific registers in Intel processors. Now with PCI configuration register support for some Intel hardware.
version 0.3.1
Important
Libmsr is no longer being actively developed. Variorum https://variorum.readthedocs.io/ is an evolution of and a successor to libmsr. Variorum can be found on github:
https://github.com/llnl/variorum
Last Update
24 March 2020
Webpages
http://software.llnl.gov/libmsr
https://github.com/llnl/libmsr
Overview
Libmsr provides an interface to accessing the model-specific registers (MSRs) on Intel platforms, which provide privileged functionality for monitoring and controlling various CPU features.
Installation
Installation is simple. You will need CMAKE version 2.8 or higher and GCC. In most cases, the installation is as follows:
$ cmake . -DCMAKE_INSTALL_PREFIX=${HOME}/build/libmsr
$ make
$ make install
The installation depends on a master.h file, which defines the offsets for
several MSRs given a particular architecture (e.g., Sandy Bridge, Ivy Bridge,
Haswell, etc.). The auto-configuration tool can be forced to use the header
file of a specific architecture or can auto-detect the architecture. To specify
a particular architecture, run cmake with the option
-DLIBMSR_TARGET_ARCH=<ARG> where ARG is in hexadecimal. In the future, we
plan to have a set of architecture-specific configuration files that can be
pre-loaded to CMake to populate the cache.
Currently supported architectures are Intel Xeon v1-3 (Sandy Bridge, Ivy Bridge, and Haswell server processors). The library technically supports all processors based on these architectures, but some features may be missing from client products. Using the wrong header file is likely to cause problems.
Supported Architectures:
2D (Sandy Bridge) 57 (Knights Landing)
3E (Ivy Bridge)
3F (Haswell)
4F (Broadwell)
55 (Skylake)*
If you are unsure of your architecture number, check the "model" field in lscpu
or /proc/cpuinfo (note that it will not be in hexadecimal).
*The Skylake support is currently experimental and requires more testing/validation.
Notes
This software depends on the files /dev/cpu/*/msr being present. Recent
kernels require additional capabilities. We have found it easier to use our own
MSR-SAFE kernel
module with R/W permissions, but running as root (or going through the bother
of adding the capabilities to the binaries) is another option.
If you need PCI configuration register (CSR) support in Libmsr, you MUST have CSR-SAFE installed. This code is not currently on Github -- you will need to request it.
Call msr_init() before using any of the APIs.
For sample code, see libmsr_test.c in the test/ directory.
Our most up-to-date documentation for Libmsr can be generated with make doc
and make latex_doc for HTML and PDF versions, respectively. There are also
some useful PDF files in the documentation/ directory.
Contact
Barry Rountree, Project Lead, [email protected]
Stephanie Brink, Developer, [email protected]
Please feel free to contact the developers with any questions or feedback.
We are collecting names of those who have previously contributed to libmsr over
the years. See the current list in the AUTHORS file. Please contact the
developers to have your name added to the list.
Release
libmsr is released under the GPLv2.1 license. For more details, see the LICENSE file.
LLNL-CODE-645430