| commit | 78e6abd244eb4f75180fdb3bc72d69a2f471feca | [log] [tgz] |
|---|---|---|
| author | David R. Jenni <david.r.jenni@gmail.com> | Wed Feb 08 11:32:58 2017 +0100 |
| committer | Russ Cox <rsc@golang.org> | Fri Feb 10 16:53:24 2017 +0000 |
| tree | 7bcb7c647653cb7642233e0eea8ef38ae333c11b | |
| parent | 6ac8ccf4b3b7ffe946b99e5031b88edc611e32ec [diff] |
sort: optimize average calculation in symMerge and doPivot. Change code of the form `i + (j-i)/2` to `int(uint(i+j) >> 1)`. The optimized average calculation uses fewer instructions to calculate the average without overflowing at the addition. Analogous to https://golang.org/cl/36332. name old time/op new time/op delta StableString1K-4 49.6µs ± 3% 49.1µs ± 8% ~ (p=0.659 n=16+19) StableInt1K-4 160µs ±10% 148µs ± 5% -7.29% (p=0.000 n=20+16) StableInt1K_Slice-4 139µs ± 4% 136µs ± 3% -2.52% (p=0.000 n=20+16) StableInt64K-4 8.84ms ± 6% 8.57ms ± 5% -3.07% (p=0.001 n=20+19) Stable1e2-4 162µs ±19% 147µs ±16% -8.79% (p=0.002 n=20+20) Stable1e4-4 31.0ms ± 5% 30.6ms ± 5% ~ (p=0.221 n=20+20) Stable1e6-4 6.37s ± 3% 6.27s ± 2% -1.67% (p=0.000 n=19+20) Change-Id: I1cea0bcb9ace8ef7e48b8fab772e41b4b2170da9 Reviewed-on: https://go-review.googlesource.com/36570 Run-TryBot: Ian Lance Taylor <iant@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Russ Cox <rsc@golang.org>
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.
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.
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.
Go is the work of hundreds of contributors. We appreciate your help!
To contribute, please read the contribution guidelines: https://golang.org/doc/contribute.html
Note that the Go project does not use GitHub pull requests, and that we use 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.