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April 12, 2024 15:59
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Mutex vs Atomics for read-heavy workload
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/* | |
goos: darwin | |
goarch: amd64 | |
pkg: github.com/github/gitrpcd/spraints/mutexvsatomic | |
cpu: Intel(R) Core(TM) i9-9980HK CPU @ 2.40GHz | |
BenchmarkMutex-16 2182556 544.1 ns/op | |
--- BENCH: BenchmarkMutex-16 | |
compare_test.go:71: maxes: [2 2 2 2 2 2 2 2 2 2] | |
compare_test.go:71: maxes: [2 2 2 2 2 2 2 2 2 2] | |
compare_test.go:71: maxes: [2 2 2 2 2 2 2 2 2 2] | |
compare_test.go:71: maxes: [2 2 2 2 2 2 2 2 2 2] | |
compare_test.go:71: maxes: [2 2 2 2 2 2 2 2 2 2] | |
compare_test.go:71: maxes: [2 2 2 2 2 2 2 2 2 2] | |
BenchmarkRWMutex-16 2672090 480.0 ns/op | |
--- BENCH: BenchmarkRWMutex-16 | |
compare_test.go:110: maxes: [2 1 2 2 2 2 2 2 2 2] | |
compare_test.go:110: maxes: [2 2 2 2 2 2 2 2 2 2] | |
compare_test.go:110: maxes: [2 2 2 2 2 2 2 2 2 2] | |
compare_test.go:110: maxes: [2 2 2 2 2 2 2 2 2 2] | |
compare_test.go:110: maxes: [2 2 2 2 2 2 2 2 2 2] | |
BenchmarkAtomic-16 1000000000 0.5505 ns/op | |
--- BENCH: BenchmarkAtomic-16 | |
compare_test.go:142: maxes: [2 2 2 2 2 2 2 2 2 2] | |
compare_test.go:142: maxes: [2 2 2 2 2 2 2 2 2 2] | |
compare_test.go:142: maxes: [2 2 2 2 2 2 2 2 2 2] | |
compare_test.go:142: maxes: [2 2 2 2 2 2 2 2 2 2] | |
compare_test.go:142: maxes: [2 2 2 2 2 2 2 2 2 2] | |
compare_test.go:142: maxes: [2 2 2 2 2 2 2 2 2 2] | |
PASS | |
ok github.com/github/gitrpcd/spraints/mutexvsatomic 5.309s | |
*/ | |
package mutexvsatomic | |
import ( | |
"sync" | |
"sync/atomic" | |
"testing" | |
) | |
func TestMutex(t *testing.T) { | |
testMutex(t, 1) | |
} | |
func BenchmarkMutex(b *testing.B) { | |
testMutex(b, b.N) | |
} | |
func TestRWMutex(t *testing.T) { | |
testRWMutex(t, 1) | |
} | |
func BenchmarkRWMutex(b *testing.B) { | |
testRWMutex(b, b.N) | |
} | |
func TestAtomic(t *testing.T) { | |
testAtomic(t, 1) | |
} | |
func BenchmarkAtomic(b *testing.B) { | |
testAtomic(b, b.N) | |
} | |
const workers = 10 | |
func testMutex(t testing.TB, n int) { | |
var data struct { | |
value int32 | |
lock sync.Mutex | |
} | |
data.value = 1 | |
// Set up a bunch of readers. | |
maxSeen := make([]chan int32, 0, workers) | |
for i := 0; i < workers; i++ { | |
s := make(chan int32) | |
maxSeen = append(maxSeen, s) | |
go func() { | |
defer close(s) | |
var myMax int32 = -1 | |
for j := 0; j < n; j++ { | |
data.lock.Lock() | |
if data.value > myMax { | |
myMax = data.value | |
} | |
data.lock.Unlock() | |
} | |
s <- myMax | |
}() | |
} | |
// Make a single write. | |
data.lock.Lock() | |
data.value += 1 | |
data.lock.Unlock() | |
// Gather the results from the readers. | |
maxes := make([]int32, 0, workers) | |
for _, s := range maxSeen { | |
maxes = append(maxes, <-s) | |
} | |
t.Logf("maxes: %v", maxes) | |
} | |
func testRWMutex(t testing.TB, n int) { | |
var data struct { | |
value int32 | |
lock sync.RWMutex | |
} | |
data.value = 1 | |
// Set up a bunch of readers. | |
maxSeen := make([]chan int32, 0, workers) | |
for i := 0; i < workers; i++ { | |
s := make(chan int32) | |
maxSeen = append(maxSeen, s) | |
go func() { | |
defer close(s) | |
var myMax int32 = -1 | |
for j := 0; j < n; j++ { | |
data.lock.RLock() | |
if data.value > myMax { | |
myMax = data.value | |
} | |
data.lock.RUnlock() | |
} | |
s <- myMax | |
}() | |
} | |
// Make a single write. | |
data.lock.Lock() | |
data.value += 1 | |
data.lock.Unlock() | |
// Gather the results from the readers. | |
maxes := make([]int32, 0, workers) | |
for _, s := range maxSeen { | |
maxes = append(maxes, <-s) | |
} | |
t.Logf("maxes: %v", maxes) | |
} | |
func testAtomic(t testing.TB, n int) { | |
var value int32 = 1 | |
// Set up a bunch of readers. | |
maxSeen := make([]chan int32, 0, workers) | |
for i := 0; i < workers; i++ { | |
s := make(chan int32) | |
maxSeen = append(maxSeen, s) | |
go func() { | |
defer close(s) | |
var myMax int32 = -1 | |
for j := 0; j < n; j++ { | |
v := atomic.LoadInt32(&value) | |
if v > myMax { | |
myMax = v | |
} | |
} | |
s <- myMax | |
}() | |
} | |
// Make a single write. | |
atomic.AddInt32(&value, 1) | |
// Gather the results from the readers. | |
maxes := make([]int32, 0, workers) | |
for _, s := range maxSeen { | |
maxes = append(maxes, <-s) | |
} | |
t.Logf("maxes: %v", maxes) | |
} |
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