| commit | 73edd7b20868825223bce7947587fb1a1ddab213 | [log] [tgz] |
|---|---|---|
| author | Brad Fitzpatrick <bradfitz@golang.org> | Sun Apr 03 18:27:17 2016 +0000 |
| committer | Brad Fitzpatrick <bradfitz@golang.org> | Sun Apr 03 23:30:43 2016 +0000 |
| tree | a66a279f310335bd6f9199d100fc5dbd399a1e21 | |
| parent | 1934a77f5a1680397481d5bc6ed85b017d1e8b38 [diff] |
cmd/link: simplify readSymName, taking advantage of bufio.Reader
Now that cmd/link uses bufio.Reader, take advantage of it.
I find this new version easier to reason about.
Reduces allocations by 1.1% when linking a basic HTTP server.
Numbers are stable with each round measuring using:
rm prof.mem; go tool link -o foo -memprofile=prof.mem -memprofilerate=1 foo.a
Before:
65.36MB of 74.53MB total (87.70%)
Dropped 157 nodes (cum <= 0.37MB)
Showing top 10 nodes out of 39 (cum >= 1.47MB)
flat flat% sum% cum cum%
21.48MB 28.81% 28.81% 21.48MB 28.81% cmd/link/internal/ld.Linklookup
16.04MB 21.52% 50.33% 16.04MB 21.52% cmd/link/internal/ld.(*objReader).readSlices
4.61MB 6.19% 56.52% 4.61MB 6.19% cmd/link/internal/ld.(*objReader).readSymName
4.51MB 6.05% 62.57% 6.32MB 8.48% cmd/link/internal/ld.writelines
4.50MB 6.03% 68.60% 4.50MB 6.03% cmd/link/internal/ld.Symgrow
4.02MB 5.39% 73.99% 4.02MB 5.39% cmd/link/internal/ld.linknew
3.98MB 5.34% 79.33% 3.98MB 5.34% cmd/link/internal/ld.setaddrplus
2.96MB 3.97% 83.30% 28.78MB 38.62% cmd/link/internal/ld.(*objReader).readRef
1.81MB 2.43% 85.73% 1.81MB 2.43% cmd/link/internal/ld.newcfaoffsetattr
1.47MB 1.97% 87.70% 1.47MB 1.97% cmd/link/internal/ld.(*objReader).readSym
After:
64.66MB of 73.87MB total (87.53%)
Dropped 156 nodes (cum <= 0.37MB)
Showing top 10 nodes out of 40 (cum >= 1.47MB)
flat flat% sum% cum cum%
21.48MB 29.08% 29.08% 21.48MB 29.08% cmd/link/internal/ld.Linklookup
16.04MB 21.71% 50.79% 16.04MB 21.71% cmd/link/internal/ld.(*objReader).readSlices
4.51MB 6.10% 56.90% 6.32MB 8.56% cmd/link/internal/ld.writelines
4.50MB 6.09% 62.99% 4.50MB 6.09% cmd/link/internal/ld.Symgrow
4.02MB 5.44% 68.42% 4.02MB 5.44% cmd/link/internal/ld.linknew
3.98MB 5.38% 73.81% 3.98MB 5.38% cmd/link/internal/ld.setaddrplus
3.90MB 5.28% 79.09% 3.90MB 5.28% cmd/link/internal/ld.(*objReader).readSymName
2.96MB 4.01% 83.09% 28.08MB 38.01% cmd/link/internal/ld.(*objReader).readRef
1.81MB 2.45% 85.55% 1.81MB 2.45% cmd/link/internal/ld.newcfaoffsetattr
1.47MB 1.99% 87.53% 1.47MB 1.99% cmd/link/internal/ld.(*objReader).readSym
Also tested locally with asserts that that the calculated length is
always correct and thus the adjName buf never reallocates.
Change-Id: I19e3e8bfa6a12bcd8b5216f6232f42c122e4f80e
Reviewed-on: https://go-review.googlesource.com/21481
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Go is an open source programming language that makes it easy to build simple, reliable, and efficient software.
For documentation about how to install and use Go, visit https://golang.org/ or load doc/install-source.html in your web browser.
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.
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
Unless otherwise noted, the Go source files are distributed under the BSD-style license found in the LICENSE file.
If you have just untarred a binary Go distribution, you need to set the environment variable $GOROOT to the full path of the go directory (the one containing this file). You can omit the variable if you unpack it into /usr/local/go, or if you rebuild from sources by running all.bash (see doc/install-source.html). You should also add the Go binary directory $GOROOT/bin to your shell's path.
For example, if you extracted the tar file into $HOME/go, you might put the following in your .profile:
export GOROOT=$HOME/go export PATH=$PATH:$GOROOT/bin
See https://golang.org/doc/install or doc/install.html for more details.