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The Go programming language
45b54ee7fb
This changes the map lookup behavior for string maps with 2-8 keys. There was already previously a fastpath for 0 items and 1 item. Now, if a string-keyed map has <= 8 items, first check all the keys for length first. If only one has the right length, then just check it for equality and avoid hashing altogether. Once the map has more than 8 items, always hash like normal. I don't know why some of the other non-string map benchmarks got faster. This was with benchtime=2s, multiple times. I haven't anything else getting slower, though. benchmark old ns/op new ns/op delta BenchmarkHashStringSpeed 37 34 -8.20% BenchmarkHashInt32Speed 32 29 -10.67% BenchmarkHashInt64Speed 31 27 -12.82% BenchmarkHashStringArraySpeed 105 99 -5.43% BenchmarkMegMap 274206 255153 -6.95% BenchmarkMegOneMap 27 23 -14.80% BenchmarkMegEqMap 148332 116089 -21.74% BenchmarkMegEmptyMap 4 3 -12.72% BenchmarkSmallStrMap 22 22 -0.89% BenchmarkMapStringKeysEight_32 42 23 -43.71% BenchmarkMapStringKeysEight_64 55 23 -56.96% BenchmarkMapStringKeysEight_1M 279688 24 -99.99% BenchmarkIntMap 16 15 -10.18% BenchmarkRepeatedLookupStrMapKey32 40 37 -8.15% BenchmarkRepeatedLookupStrMapKey1M 287918 272980 -5.19% BenchmarkNewEmptyMap 156 130 -16.67% R=golang-dev, khr CC=golang-dev https://golang.org/cl/7641057 |
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This is the source code repository for the Go programming language.
For documentation about how to install and use Go,
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--
Binary Distribution Notes
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 README). 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.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 doc/install.html for more details.