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https://github.com/golang/go
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1fa7029425
Combine NoScan allocations < 16 bytes into a single memory block.
Reduces number of allocations on json/garbage benchmarks by 10+%.
json-1
allocated 8039872 7949194 -1.13%
allocs 105774 93776 -11.34%
cputime 156200000 100700000 -35.53%
gc-pause-one 4908873 3814853 -22.29%
gc-pause-total 2748969 2899288 +5.47%
rss 52674560 43560960 -17.30%
sys-gc 3796976 3256304 -14.24%
sys-heap 43843584 35192832 -19.73%
sys-other 5589312 5310784 -4.98%
sys-stack 393216 393216 +0.00%
sys-total 53623088 44153136 -17.66%
time 156193436 100886714 -35.41%
virtual-mem 256548864 256540672 -0.00%
garbage-1
allocated 2996885 2932982 -2.13%
allocs 62904 55200 -12.25%
cputime 17470000 17400000 -0.40%
gc-pause-one 932757485 925806143 -0.75%
gc-pause-total 4663787 4629030 -0.75%
rss 1151074304 1133670400 -1.51%
sys-gc 66068352 65085312 -1.49%
sys-heap 1039728640 1024065536 -1.51%
sys-other 38038208 37485248 -1.45%
sys-stack 8650752 8781824 +1.52%
sys-total 1152485952 1135417920 -1.48%
time 17478088 17418005 -0.34%
virtual-mem 1343709184 1324204032 -1.45%
LGTM=iant, bradfitz
R=golang-codereviews, dave, iant, rsc, bradfitz
CC=golang-codereviews, khr
https://golang.org/cl/38750047
62 lines
1.5 KiB
Go
62 lines
1.5 KiB
Go
// run
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// Copyright 2014 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// Test finalizers work for tiny (combined) allocations.
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package main
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import (
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"runtime"
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"sync/atomic"
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"time"
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)
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func main() {
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// Does not work on 32-bits due to partially conservative GC.
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// Try to enable when we have fully precise GC.
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if runtime.GOARCH != "amd64" {
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return
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}
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// Likewise for gccgo.
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if runtime.Compiler == "gccgo" {
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return
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}
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N := int32(100)
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count := N
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done := make([]bool, N)
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for i := int32(0); i < N; i++ {
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x := i // subject to tiny alloc
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// the closure must be big enough to be combined
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runtime.SetFinalizer(&x, func(p *int32) {
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// Check that p points to the correct subobject of the tiny allocation.
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// It's a bit tricky, because we can't capture another variable
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// with the expected value (it would be combined as well).
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if *p < 0 || *p >= N {
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println("got", *p)
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panic("corrupted")
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}
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if done[*p] {
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println("got", *p)
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panic("already finalized")
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}
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done[*p] = true
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atomic.AddInt32(&count, -1)
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})
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}
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for i := 0; i < 4; i++ {
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runtime.GC()
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time.Sleep(10 * time.Millisecond)
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}
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// Some of the finalizers may not be executed,
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// if the outermost allocations are combined with something persistent.
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// Currently 4 int32's are combined into a 16-byte block,
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// ensure that most of them are finalized.
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if count >= N/4 {
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println(count, "out of", N, "finalizer are not called")
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panic("not all finalizers are called")
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}
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}
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