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| author | Carlo Alberto Ferraris <cafxx@strayorange.com> | 2019-08-24 08:59:01 +0900 |
|---|---|---|
| committer | Emmanuel Odeke <emm.odeke@gmail.com> | 2019-09-29 14:27:05 +0000 |
| commit | 931365763a294950200096d071a35f799ffade2c (patch) | |
| tree | ad6eb4ac98137df44e6a3b0dc74f5c7bcb4f378e /src | |
| parent | 57662b1575030aa09043cd7a48425abdc6e0e0a3 (diff) | |
| download | go-931365763a294950200096d071a35f799ffade2c.tar.xz | |
math/rand: devirtualize interface in lockedSource
Avoid interface calls, enable inlining, and store the rngSource close to the
Mutex to exploit better memory locality.
Also add a benchmark to properly measure the threadsafe nature of globalRand.
On a linux/amd64 VM:
name old time/op new time/op delta
Int63Threadsafe-4 36.4ns ±12% 20.6ns ±11% -43.52% (p=0.000 n=30+30)
Int63ThreadsafeParallel-4 79.3ns ± 5% 56.5ns ± 5% -28.69% (p=0.000 n=29+30)
Change-Id: I6ab912c1a1e9afc7bacd8e72c82d4d50d546a510
Reviewed-on: https://go-review.googlesource.com/c/go/+/191538
Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com>
Run-TryBot: Emmanuel Odeke <emm.odeke@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Diffstat (limited to 'src')
| -rw-r--r-- | src/cmd/compile/internal/gc/inl_test.go | 4 | ||||
| -rw-r--r-- | src/math/rand/rand.go | 7 | ||||
| -rw-r--r-- | src/math/rand/rand_test.go | 8 |
3 files changed, 17 insertions, 2 deletions
diff --git a/src/cmd/compile/internal/gc/inl_test.go b/src/cmd/compile/internal/gc/inl_test.go index a0f56e776b..77c398af82 100644 --- a/src/cmd/compile/internal/gc/inl_test.go +++ b/src/cmd/compile/internal/gc/inl_test.go @@ -148,6 +148,10 @@ func TestIntendedInlining(t *testing.T) { "addVW", "subVW", }, + "math/rand": { + "(*rngSource).Int63", + "(*rngSource).Uint64", + }, } if runtime.GOARCH != "386" && runtime.GOARCH != "mips64" && runtime.GOARCH != "mips64le" { diff --git a/src/math/rand/rand.go b/src/math/rand/rand.go index 04382e6208..6e5eb4ba6a 100644 --- a/src/math/rand/rand.go +++ b/src/math/rand/rand.go @@ -285,7 +285,10 @@ func read(p []byte, int63 func() int64, readVal *int64, readPos *int8) (n int, e * Top-level convenience functions */ -var globalRand = New(&lockedSource{src: NewSource(1).(Source64)}) +var globalRand = New(&lockedSource{src: NewSource(1).(*rngSource)}) + +// Type assert that globalRand's source is a lockedSource whose src is a *rngSource. +var _ *rngSource = globalRand.src.(*lockedSource).src // Seed uses the provided seed value to initialize the default Source to a // deterministic state. If Seed is not called, the generator behaves as @@ -373,7 +376,7 @@ func ExpFloat64() float64 { return globalRand.ExpFloat64() } type lockedSource struct { lk sync.Mutex - src Source64 + src *rngSource } func (r *lockedSource) Int63() (n int64) { diff --git a/src/math/rand/rand_test.go b/src/math/rand/rand_test.go index ee9c8f8e84..e037aaed0e 100644 --- a/src/math/rand/rand_test.go +++ b/src/math/rand/rand_test.go @@ -565,6 +565,14 @@ func BenchmarkInt63Threadsafe(b *testing.B) { } } +func BenchmarkInt63ThreadsafeParallel(b *testing.B) { + b.RunParallel(func(pb *testing.PB) { + for pb.Next() { + Int63() + } + }) +} + func BenchmarkInt63Unthreadsafe(b *testing.B) { r := New(NewSource(1)) for n := b.N; n > 0; n-- { |