| // Copyright 2013 The Go Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style |
| // license that can be found in the LICENSE file. |
| |
| // The file contains tests that can not run under race detector for some reason. |
| // +build !race |
| |
| package runtime_test |
| |
| import ( |
| "runtime" |
| "sync/atomic" |
| "testing" |
| ) |
| |
| // Syscall tests split stack between Entersyscall and Exitsyscall under race detector. |
| func BenchmarkSyscall(b *testing.B) { |
| benchmarkSyscall(b, 0, 1) |
| } |
| |
| func BenchmarkSyscallWork(b *testing.B) { |
| benchmarkSyscall(b, 100, 1) |
| } |
| |
| func BenchmarkSyscallExcess(b *testing.B) { |
| benchmarkSyscall(b, 0, 4) |
| } |
| |
| func BenchmarkSyscallExcessWork(b *testing.B) { |
| benchmarkSyscall(b, 100, 4) |
| } |
| |
| func benchmarkSyscall(b *testing.B, work, excess int) { |
| const CallsPerSched = 1000 |
| procs := runtime.GOMAXPROCS(-1) * excess |
| N := int32(b.N / CallsPerSched) |
| c := make(chan bool, procs) |
| for p := 0; p < procs; p++ { |
| go func() { |
| foo := 42 |
| for atomic.AddInt32(&N, -1) >= 0 { |
| runtime.Gosched() |
| for g := 0; g < CallsPerSched; g++ { |
| runtime.Entersyscall() |
| for i := 0; i < work; i++ { |
| foo *= 2 |
| foo /= 2 |
| } |
| runtime.Exitsyscall() |
| } |
| } |
| c <- foo == 42 |
| }() |
| } |
| for p := 0; p < procs; p++ { |
| <-c |
| } |
| } |