Float type from a mutex to atomic bit array in a manner akin to
Google Guava's AtomicDouble[0], including adding a benchmark for the
type (benchcmp included below) along with some expvar_test.go cruft
being fixed.
benchmark old ns/op new ns/op delta
BenchmarkFloatSet 115 9.37 -91.85%
BenchmarkFloatAdd 114 17.1 -85.00%
benchmark old allocs new allocs delta
BenchmarkFloatSet 0 0 +0.00%
BenchmarkFloatAdd 0 0 +0.00%
benchmark old bytes new bytes delta
BenchmarkFloatSet 0 0 +0.00%
BenchmarkFloatAdd 0 0 +0.00%
[0] - http://goo.gl/m4dtlI
Change-Id: I4ce6a913734ec692e3ed243f6e6f7c11da4c6036
Reviewed-on: https://go-review.googlesource.com/3687
Reviewed-by: Rob Pike <r@golang.org>
These benchmarks are only for functions commonly used in loops. The
other functions are typically used for inspection or setup and thus are
not performance sensitive.
Change-Id: I8d0a0ba2d8234ecacb40fa3aa9077bf93c8fe89c
Reviewed-on: https://go-review.googlesource.com/3680
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Using a mutex to protect a single int operation is quite heavyweight.
Using sync/atomic provides much better performance. This change was
benchmarked as such:
BenchmarkSync 10000000 139 ns/op
BenchmarkAtomic 200000000 9.90 ns/op
package blah
import (
"sync"
"sync/atomic"
"testing"
)
type Int struct {
mu sync.RWMutex
i int64
}
func (v *Int) Add(delta int64) {
v.mu.Lock()
defer v.mu.Unlock()
v.i += delta
}
type AtomicInt struct {
i int64
}
func (v *AtomicInt) Add(delta int64) {
atomic.AddInt64(&v.i, delta)
}
func BenchmarkSync(b *testing.B) {
s := new(Int)
for i := 0; i < b.N; i++ {
s.Add(1)
}
}
func BenchmarkAtomic(b *testing.B) {
s := new(AtomicInt)
for i := 0; i < b.N; i++ {
s.Add(1)
}
}
Change-Id: I6998239c785967647351bbfe8533c38e4894543b
Reviewed-on: https://go-review.googlesource.com/3430
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>