Make use of the newly-enabled limited midstack inlining.
Similar changes will be done in followup CLs.
name old time/op new time/op delta
MutexUncontended 19.3ns ± 1% 18.9ns ± 0% -1.92% (p=0.000 n=20+19)
MutexUncontended-4 5.24ns ± 0% 4.75ns ± 1% -9.25% (p=0.000 n=20+20)
MutexUncontended-16 2.10ns ± 0% 2.05ns ± 0% -2.38% (p=0.000 n=15+19)
Mutex 19.6ns ± 0% 19.3ns ± 1% -1.92% (p=0.000 n=20+17)
Mutex-4 54.6ns ± 5% 52.4ns ± 4% -4.09% (p=0.000 n=20+20)
Mutex-16 133ns ± 5% 139ns ± 2% +4.23% (p=0.000 n=20+16)
MutexSlack 33.4ns ± 2% 18.9ns ± 1% -43.56% (p=0.000 n=19+20)
MutexSlack-4 206ns ± 5% 225ns ± 8% +9.12% (p=0.000 n=20+18)
MutexSlack-16 89.4ns ± 1% 98.4ns ± 1% +10.10% (p=0.000 n=18+17)
MutexWork 60.5ns ± 0% 58.2ns ± 3% -3.75% (p=0.000 n=12+20)
MutexWork-4 105ns ± 5% 103ns ± 7% -1.68% (p=0.007 n=20+20)
MutexWork-16 157ns ± 1% 163ns ± 2% +3.90% (p=0.000 n=18+18)
MutexWorkSlack 70.2ns ± 5% 57.7ns ± 1% -17.81% (p=0.000 n=19+20)
MutexWorkSlack-4 277ns ±13% 276ns ±13% ~ (p=0.682 n=20+19)
MutexWorkSlack-16 156ns ± 0% 147ns ± 0% -5.62% (p=0.000 n=16+14)
MutexNoSpin 966ns ± 0% 968ns ± 0% +0.11% (p=0.029 n=15+20)
MutexNoSpin-4 269ns ± 4% 270ns ± 2% ~ (p=0.807 n=20+19)
MutexNoSpin-16 122ns ± 0% 120ns ± 4% -1.63% (p=0.000 n=19+19)
MutexSpin 3.13µs ± 0% 3.13µs ± 1% +0.16% (p=0.004 n=18+20)
MutexSpin-4 826ns ± 1% 832ns ± 2% +0.74% (p=0.000 n=19+16)
MutexSpin-16 397ns ± 1% 395ns ± 0% -0.50% (p=0.000 n=19+17)
RWMutexUncontended 71.4ns ± 0% 69.5ns ± 0% -2.72% (p=0.000 n=16+20)
RWMutexUncontended-4 18.4ns ± 4% 17.5ns ± 0% -4.92% (p=0.000 n=20+18)
RWMutexUncontended-16 8.01ns ± 0% 7.92ns ± 0% -1.15% (p=0.000 n=18+18)
RWMutexWrite100 24.9ns ± 0% 24.9ns ± 1% ~ (p=0.099 n=19+20)
RWMutexWrite100-4 46.5ns ± 3% 46.2ns ± 4% ~ (p=0.253 n=17+19)
RWMutexWrite100-16 68.9ns ± 3% 69.9ns ± 5% +1.46% (p=0.012 n=18+20)
RWMutexWrite10 27.1ns ± 0% 27.0ns ± 2% ~ (p=0.128 n=17+20)
RWMutexWrite10-4 34.8ns ± 1% 34.7ns ± 2% ~ (p=0.180 n=20+18)
RWMutexWrite10-16 37.5ns ± 2% 37.2ns ± 4% -0.89% (p=0.023 n=20+20)
RWMutexWorkWrite100 164ns ± 0% 164ns ± 0% ~ (p=0.106 n=12+20)
RWMutexWorkWrite100-4 186ns ± 3% 193ns ± 3% +3.46% (p=0.000 n=20+20)
RWMutexWorkWrite100-16 204ns ± 2% 210ns ± 3% +2.96% (p=0.000 n=18+20)
RWMutexWorkWrite10 153ns ± 0% 153ns ± 0% -0.20% (p=0.017 n=20+19)
RWMutexWorkWrite10-4 179ns ± 1% 178ns ± 2% ~ (p=0.215 n=19+20)
RWMutexWorkWrite10-16 191ns ± 1% 192ns ± 2% ~ (p=0.166 n=15+19)
linux/amd64 bin/go
14630572 (previous commit
14605947, +24625/+0.17%)
Change-Id: I3f9d1765801fe0b8deb1bc2728b8bba8a7508e23
Reviewed-on: https://go-review.googlesource.com/c/go/+/148958
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
}
//go:linkname sync_runtime_Semrelease sync.runtime_Semrelease
-func sync_runtime_Semrelease(addr *uint32, handoff bool) {
- semrelease1(addr, handoff)
+func sync_runtime_Semrelease(addr *uint32, handoff bool, skipframes int) {
+ semrelease1(addr, handoff, skipframes)
}
//go:linkname sync_runtime_SemacquireMutex sync.runtime_SemacquireMutex
}
func semrelease(addr *uint32) {
- semrelease1(addr, false)
+ semrelease1(addr, false, 0)
}
-func semrelease1(addr *uint32, handoff bool) {
+func semrelease1(addr *uint32, handoff bool, skipframes int) {
root := semroot(addr)
atomic.Xadd(addr, 1)
if s != nil { // May be slow, so unlock first
acquiretime := s.acquiretime
if acquiretime != 0 {
- mutexevent(t0-acquiretime, 3)
+ mutexevent(t0-acquiretime, 3+skipframes)
}
if s.ticket != 0 {
throw("corrupted semaphore ticket")
if handoff && cansemacquire(addr) {
s.ticket = 1
}
- readyWithTime(s, 5)
+ readyWithTime(s, 5+skipframes)
}
}
// Fast path: drop lock bit.
new := atomic.AddInt32(&m.state, -mutexLocked)
+ if new != 0 {
+ // Outlined slow path to allow inlining the fast path.
+ // To hide unlockSlow during tracing we skip one extra frame when tracing GoUnblock.
+ m.unlockSlow(new)
+ }
+}
+
+func (m *Mutex) unlockSlow(new int32) {
if (new+mutexLocked)&mutexLocked == 0 {
throw("sync: unlock of unlocked mutex")
}
// Grab the right to wake someone.
new = (old - 1<<mutexWaiterShift) | mutexWoken
if atomic.CompareAndSwapInt32(&m.state, old, new) {
- runtime_Semrelease(&m.sema, false)
+ runtime_Semrelease(&m.sema, false, 1)
return
}
old = m.state
// Note: mutexLocked is not set, the waiter will set it after wakeup.
// But mutex is still considered locked if mutexStarving is set,
// so new coming goroutines won't acquire it.
- runtime_Semrelease(&m.sema, true)
+ runtime_Semrelease(&m.sema, true, 1)
}
}
func HammerSemaphore(s *uint32, loops int, cdone chan bool) {
for i := 0; i < loops; i++ {
Runtime_Semacquire(s)
- Runtime_Semrelease(s, false)
+ Runtime_Semrelease(s, false, 0)
}
cdone <- true
}
// It is intended as a simple wakeup primitive for use by the synchronization
// library and should not be used directly.
// If handoff is true, pass count directly to the first waiter.
-func runtime_Semrelease(s *uint32, handoff bool)
+// skipframes is the number of frames to omit during tracing, counting from
+// runtime_Semrelease's caller.
+func runtime_Semrelease(s *uint32, handoff bool, skipframes int)
// Approximation of notifyList in runtime/sema.go. Size and alignment must
// agree.
b.RunParallel(func(pb *testing.PB) {
sem := new(PaddedSem)
for pb.Next() {
- Runtime_Semrelease(&sem.sem, false)
+ Runtime_Semrelease(&sem.sem, false, 0)
Runtime_Semacquire(&sem.sem)
}
})
b.RunParallel(func(pb *testing.PB) {
foo := 0
for pb.Next() {
- Runtime_Semrelease(&sem, false)
+ Runtime_Semrelease(&sem, false, 0)
if work {
for i := 0; i < 100; i++ {
foo *= 2
Runtime_Semacquire(&sem)
}
_ = foo
- Runtime_Semrelease(&sem, false)
+ Runtime_Semrelease(&sem, false, 0)
})
}
// A writer is pending.
if atomic.AddInt32(&rw.readerWait, -1) == 0 {
// The last reader unblocks the writer.
- runtime_Semrelease(&rw.writerSem, false)
+ runtime_Semrelease(&rw.writerSem, false, 0)
}
}
if race.Enabled {
}
// Unblock blocked readers, if any.
for i := 0; i < int(r); i++ {
- runtime_Semrelease(&rw.readerSem, false)
+ runtime_Semrelease(&rw.readerSem, false, 0)
}
// Allow other writers to proceed.
rw.w.Unlock()
// Reset waiters count to 0.
*statep = 0
for ; w != 0; w-- {
- runtime_Semrelease(semap, false)
+ runtime_Semrelease(semap, false, 0)
}
}
--- /dev/null
+// +build !nacl,!386
+// errorcheck -0 -m
+
+// Copyright 2019 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.
+
+// Test, using compiler diagnostic flags, that inlining of functions
+// imported from the sync package is working.
+// Compiles but does not run.
+// FIXME: nacl-386 is excluded as inlining currently does not work there.
+
+package foo
+
+import (
+ "sync"
+)
+
+var mutex *sync.Mutex
+
+func small5() { // ERROR "can inline small5"
+ // the Unlock fast path should be inlined
+ mutex.Unlock() // ERROR "inlining call to sync\.\(\*Mutex\)\.Unlock" "&sync\.m\.state escapes to heap"
+}