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log: Optimize formatting time in header with avoiding buffer copy in ioa #20267

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hnakamur opened this issue May 6, 2017 · 4 comments
Closed

log: Optimize formatting time in header with avoiding buffer copy in ioa #20267

hnakamur opened this issue May 6, 2017 · 4 comments
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FrozenDueToAge Performance
Milestone
Go1.10

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@hnakamur
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hnakamur commented May 6, 2017

Please answer these questions before submitting your issue. Thanks!

What version of Go are you using (go version)?

go version go1.8.1 linux/amd64

The target source code version: e94b9d4

What operating system and processor architecture are you using (go env)?

$ go env
GOARCH="amd64"
GOBIN=""
GOEXE=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOOS="linux"
GOPATH="/home/hnakamur/go"
GORACE=""
GOROOT="/usr/local/go"
GOTOOLDIR="/usr/local/go/pkg/tool/linux_amd64"
GCCGO="gccgo"
CC="gcc"
GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build252988026=/tmp/go-build -gno-record-gcc-switches"
CXX="g++"
CGO_ENABLED="1"
PKG_CONFIG="pkg-config"
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"

What did you do?

This issue is not an error report.
I optimized formatting time in log headers a little bit.

name                    old time/op    new time/op    delta
Println-2                  543ns ± 1%     474ns ± 0%  -12.67%  (p=0.000 n=8+9)
PrintlnMicoroseconds-2     580ns ± 1%     511ns ± 0%  -11.89%  (p=0.000 n=10+10)

name                    old alloc/op   new alloc/op   delta
Println-2                  21.0B ± 0%     21.0B ± 0%     ~     (all equal)
PrintlnMicoroseconds-2     21.0B ± 0%     21.0B ± 0%     ~     (all equal)

name                    old allocs/op  new allocs/op  delta
Println-2                   2.00 ± 0%      2.00 ± 0%     ~     (all equal)
PrintlnMicoroseconds-2      2.00 ± 0%      2.00 ± 0%     ~     (all equal)

Could you take a look at the following two commits and tell me what do you think?

Before my optimization, I added BenchmarkPrintlnMicoroseconds to be used alongside with existing BenchmarkPrintln.
https://github.com/hnakamur/go/commit/3442066c11696d05a1927d5467b4c1493cbd9ec7

Then I optimized itoa.
Actually itoa remains the same for backward compatibility.
I added itoaPad which avoids a buffer copy.
https://github.com/hnakamur/go/commit/a95dd6dc3bcd6e4e5264f06859a7dc3b368545ef

What did you expect to see?

What did you see instead?
@bradfitz
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bradfitz commented May 6, 2017

Could you take a look at the following two commits and tell me what do you think?

We can only accept code submitted via Gerrit which we have configured to require that you've submitted a CLA.

See https://golang.org/doc/contribute.html for how to send a change, including an optimization change.

@bradfitz bradfitz added this to the Go1.10 milestone May 6, 2017
@gopherbot
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CL https://golang.org/cl/42891 mentions this issue.

@hnakamur
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hnakamur commented May 6, 2017

Thanks for your comment!
I sent the change for review at https://go-review.googlesource.com/c/42891/

@hnakamur
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I'm closing this issue since now its' got 12% slower this this patch after rebase.
https://go-review.googlesource.com/c/go/+/42891

@golang golang locked and limited conversation to collaborators Oct 14, 2018
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