9c2be4c22d
Rationale: small buffer optimization does not work and it has
made things slower since 2014. Until we can make it work,
we should prefer simpler code that also turns out to be more
efficient.
With this change, it's possible to use
NewBuffer(make([]byte, 0, bootstrapSize)) to get the desired
stack-allocated initial buffer since escape analysis can
prove the created slice to be non-escaping.
New implementation key points:
- Zero value bytes.Buffer performs better than before
- You can have a truly stack-allocated buffer, and it's not even limited to 64 bytes
- The unsafe.Sizeof(bytes.Buffer{}) is reduced significantly
- Empty writes don't cause allocations
Buffer benchmarks from bytes package:
name old time/op new time/op delta
ReadString-8 9.20µs ± 1% 9.22µs ± 1% ~ (p=0.148 n=10+10)
WriteByte-8 28.1µs ± 0% 26.2µs ± 0% -6.78% (p=0.000 n=10+10)
WriteRune-8 64.9µs ± 0% 65.0µs ± 0% +0.16% (p=0.000 n=10+10)
BufferNotEmptyWriteRead-8 469µs ± 0% 461µs ± 0% -1.76% (p=0.000 n=9+10)
BufferFullSmallReads-8 108µs ± 0% 108µs ± 0% -0.21% (p=0.000 n=10+10)
name old speed new speed delta
ReadString-8 3.56GB/s ± 1% 3.55GB/s ± 1% ~ (p=0.165 n=10+10)
WriteByte-8 146MB/s ± 0% 156MB/s ± 0% +7.26% (p=0.000 n=9+10)
WriteRune-8 189MB/s ± 0% 189MB/s ± 0% -0.16% (p=0.000 n=10+10)
name old alloc/op new alloc/op delta
ReadString-8 32.8kB ± 0% 32.8kB ± 0% ~ (all equal)
WriteByte-8 0.00B 0.00B ~ (all equal)
WriteRune-8 0.00B 0.00B ~ (all equal)
BufferNotEmptyWriteRead-8 4.72kB ± 0% 4.67kB ± 0% -1.02% (p=0.000 n=10+10)
BufferFullSmallReads-8 3.44kB ± 0% 3.33kB ± 0% -3.26% (p=0.000 n=10+10)
name old allocs/op new allocs/op delta
ReadString-8 1.00 ± 0% 1.00 ± 0% ~ (all equal)
WriteByte-8 0.00 0.00 ~ (all equal)
WriteRune-8 0.00 0.00 ~ (all equal)
BufferNotEmptyWriteRead-8 3.00 ± 0% 3.00 ± 0% ~ (all equal)
BufferFullSmallReads-8 3.00 ± 0% 2.00 ± 0% -33.33% (p=0.000 n=10+10)
The most notable thing in go1 benchmarks is reduced allocs in HTTPClientServer (-1 alloc):
HTTPClientServer-8 64.0 ± 0% 63.0 ± 0% -1.56% (p=0.000 n=10+10)
For more explanations and benchmarks see the referenced issue.
Updates #7921
Change-Id: Ica0bf85e1b70fb4f5dc4f6a61045e2cf4ef72aa3
Reviewed-on: https://go-review.googlesource.com/133715
Reviewed-by: Martin Möhrmann <moehrmann@google.com>
Reviewed-by: Robert Griesemer <gri@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
|
||
|---|---|---|
| .github | ||
| api | ||
| doc | ||
| lib/time | ||
| misc | ||
| src | ||
| test | ||
| .gitattributes | ||
| .gitignore | ||
| AUTHORS | ||
| CONTRIBUTING.md | ||
| CONTRIBUTORS | ||
| favicon.ico | ||
| LICENSE | ||
| PATENTS | ||
| README.md | ||
| robots.txt | ||
The Go Programming Language
Go is an open source programming language that makes it easy to build simple, reliable, and efficient software.
Gopher image by Renee French, licensed under Creative Commons 3.0 Attributions license.
Our canonical Git repository is located at https://go.googlesource.com/go. There is a mirror of the repository at https://github.com/golang/go.
Unless otherwise noted, the Go source files are distributed under the BSD-style license found in the LICENSE file.
Download and Install
Binary Distributions
Official binary distributions are available at https://golang.org/dl/.
After downloading a binary release, visit https://golang.org/doc/install or load doc/install.html in your web browser for installation instructions.
Install From Source
If a binary distribution is not available for your combination of operating system and architecture, visit https://golang.org/doc/install/source or load doc/install-source.html in your web browser for source installation instructions.
Contributing
Go is the work of thousands of contributors. We appreciate your help!
To contribute, please read the contribution guidelines: https://golang.org/doc/contribute.html
Note that the Go project uses the issue tracker for bug reports and proposals only. See https://golang.org/wiki/Questions for a list of places to ask questions about the Go language.