runtime: refactor Syscall benchmark
And add a benchmark where #goroutines>GOMAXPROCS,
because it's the most interesting case.
Current results on darwin/amd64, Intel Core 2 Duo 2.13 GHz, 2 cores:
BenchmarkSyscall 100000000 56.0 ns/op
BenchmarkSyscall-2 50000000 57.2 ns/op
BenchmarkSyscallWork 10000000 635 ns/op
BenchmarkSyscallWork-2 10000000 315 ns/op
BenchmarkSyscallExcess 1000000 2698 ns/op
BenchmarkSyscallExcess-2 5000000 1192 ns/op
BenchmarkSyscallExcessWork 1000000 2832 ns/op
BenchmarkSyscallExcessWork-2 2000000 1966 ns/op
R=golang-dev, r
CC=golang-dev
https://golang.org/cl/7415044
diff --git a/src/pkg/runtime/proc_test.go b/src/pkg/runtime/proc_test.go
index b2fa4c9..21fb9c2 100644
--- a/src/pkg/runtime/proc_test.go
+++ b/src/pkg/runtime/proc_test.go
@@ -152,31 +152,24 @@
}
func BenchmarkSyscall(b *testing.B) {
- const CallsPerSched = 1000
- procs := runtime.GOMAXPROCS(-1)
- N := int32(b.N / CallsPerSched)
- c := make(chan bool, procs)
- for p := 0; p < procs; p++ {
- go func() {
- for atomic.AddInt32(&N, -1) >= 0 {
- runtime.Gosched()
- for g := 0; g < CallsPerSched; g++ {
- runtime.Entersyscall()
- runtime.Exitsyscall()
- }
- }
- c <- true
- }()
- }
- for p := 0; p < procs; p++ {
- <-c
- }
+ 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
- const LocalWork = 100
- procs := runtime.GOMAXPROCS(-1)
+ procs := runtime.GOMAXPROCS(-1) * excess
N := int32(b.N / CallsPerSched)
c := make(chan bool, procs)
for p := 0; p < procs; p++ {
@@ -186,7 +179,7 @@
runtime.Gosched()
for g := 0; g < CallsPerSched; g++ {
runtime.Entersyscall()
- for i := 0; i < LocalWork; i++ {
+ for i := 0; i < work; i++ {
foo *= 2
foo /= 2
}
