go-stm
import "github.com/decillion/go-stm"
Package stm is a software transactional memory implementation for Go, which is based on the Transactional Locking II (TL2) proposed by Dice et al. https://doi.org/10.1007/11864219_14
Documents
See the godoc page for further information. Here is a blog post about go-stm (in Japanese).
Example
// There are two bank accounts of Alice and Bob.
accountA := New(100)
accountB := New(0)
// Transfer 20 from Alice's account to Bob's one.
transfer := func(rec *TRec) interface{} {
currA := rec.Load(accountA).(int)
currB := rec.Load(accountB).(int)
rec.Store(accountA, currA-20)
rec.Store(accountB, currB+20)
return nil
}
Atomically(transfer)
// Check the balance of accounts of Alice and Bob.
inquiries := func(rec *TRec) interface{} {
balance := make(map[*TVar]int)
balance[accountA] = rec.Load(accountA).(int)
balance[accountB] = rec.Load(accountB).(int)
return balance
}
balance := Atomically(inquiries).(map[*TVar]int)
fmt.Printf("The account of Alice holds %v.\nThe account of Bob holds %v.",
balance[accountA], balance[accountB])
// Output:
// The account of Alice holds 80.
// The account of Bob holds 20.Benchmark
There exists an another STM package written by lukechampine. The lukechampine's package provides a richer interface but is less efficient than the present package. Here is the result of a very simple benchmark, in which two transactional variables are atomically incremented or read. The benchmark is taken at a DigitalOcean's High CPU Droplet with 32 cores.
Benchmark_Read90Write10_decillion-2 10000000 230 ns/op
Benchmark_Read90Write10_decillion-4 10000000 156 ns/op
Benchmark_Read90Write10_decillion-8 10000000 144 ns/op
Benchmark_Read90Write10_decillion-16 10000000 214 ns/op
Benchmark_Read90Write10_decillion-32 5000000 289 ns/op
Benchmark_Read90Write10_lukechampine-2 2000000 715 ns/op
Benchmark_Read90Write10_lukechampine-4 2000000 761 ns/op
Benchmark_Read90Write10_lukechampine-8 2000000 822 ns/op
Benchmark_Read90Write10_lukechampine-16 2000000 912 ns/op
Benchmark_Read90Write10_lukechampine-32 2000000 966 ns/op