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006d7e180e
CmdName was re-opening the running executable and scanning it in
64KiB chunks for the Go modinfo markers on every call. The same
modinfo is already parsed at startup and exposed via
runtime/debug.ReadBuildInfo, so prefer that on non-Windows. Windows
still takes the scanning path because its GUI-binary override keys
off the on-disk executable name.
benchstat of BenchmarkCmdName (Linux, before vs after):
goos: linux
goarch: amd64
pkg: tailscale.com/version
cpu: Intel(R) Xeon(R) 6975P-C
│ /tmp/old.txt │ /tmp/new.txt │
│ sec/op │ sec/op vs base │
CmdName-16 556045.5n ± 1% 825.6n ± 1% -99.85% (p=0.000 n=10)
│ /tmp/old.txt │ /tmp/new.txt │
│ B/op │ B/op vs base │
CmdName-16 64.587Ki ± 0% 1.156Ki ± 0% -98.21% (p=0.000 n=10)
│ /tmp/old.txt │ /tmp/new.txt │
│ allocs/op │ allocs/op vs base │
CmdName-16 8.000 ± 0% 7.000 ± 0% -12.50% (p=0.000 n=10)
Fixes #19486
Change-Id: I925c5e28b64815a602459beb6c8dab8779339a6c
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
72 lines
1.5 KiB
Go
72 lines
1.5 KiB
Go
// Copyright (c) Tailscale Inc & contributors
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// SPDX-License-Identifier: BSD-3-Clause
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package version_test
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import (
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"bytes"
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"os"
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"path"
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"runtime/debug"
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"testing"
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ts "tailscale.com"
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"tailscale.com/version"
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)
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func TestAlpineTag(t *testing.T) {
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if tag := readAlpineTag(t, "../Dockerfile.base"); tag == "" {
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t.Fatal(`"FROM alpine:" not found in Dockerfile.base`)
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} else if tag != ts.AlpineDockerTag {
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t.Errorf("alpine version mismatch: Dockerfile.base has %q; ALPINE.txt has %q", tag, ts.AlpineDockerTag)
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}
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if tag := readAlpineTag(t, "../Dockerfile"); tag == "" {
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t.Fatal(`"FROM alpine:" not found in Dockerfile`)
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} else if tag != ts.AlpineDockerTag {
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t.Errorf("alpine version mismatch: Dockerfile has %q; ALPINE.txt has %q", tag, ts.AlpineDockerTag)
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}
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}
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func readAlpineTag(t *testing.T, file string) string {
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f, err := os.ReadFile(file)
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if err != nil {
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t.Fatal(err)
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}
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for line := range bytes.SplitSeq(f, []byte{'\n'}) {
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line = bytes.TrimSpace(line)
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_, suf, ok := bytes.Cut(line, []byte("FROM alpine:"))
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if !ok {
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continue
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}
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return string(suf)
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}
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return ""
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}
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func TestShortAllocs(t *testing.T) {
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allocs := int(testing.AllocsPerRun(10000, func() {
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_ = version.Short()
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}))
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if allocs > 0 {
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t.Errorf("allocs = %v; want 0", allocs)
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}
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}
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func BenchmarkCmdName(b *testing.B) {
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b.ReportAllocs()
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for b.Loop() {
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_ = version.CmdName()
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}
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}
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func BenchmarkReadBuildInfo(b *testing.B) {
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b.ReportAllocs()
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for b.Loop() {
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info, ok := debug.ReadBuildInfo()
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if !ok {
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b.Fatal("ReadBuildInfo failed")
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}
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_ = path.Base(info.Path)
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}
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}
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