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The Go programming language
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This implementation allows a goroutine to do successive acquisitions of a mutex even if there are blocked goroutines. Moreover, it allows a newcomer goroutine to acquire a mutex ahead of blocked goroutines (that is, it does not enforce FIFO). On implementation level it's achieved by separating waiter count and locked flag. Benchmark results on HP Z600 (2 x Xeon E5620, 8 HT cores, 2.40GHz) are as follows (with 4631059 "replace Semacquire/Semrelease implementation" patch applied): benchmark old ns/op new ns/op delta sync_test.BenchmarkMutexUncontended 24.10 25.40 +5.39% sync_test.BenchmarkMutexUncontended-2 12.00 13.00 +8.33% sync_test.BenchmarkMutexUncontended-4 6.06 6.83 +12.71% sync_test.BenchmarkMutexUncontended-8 3.63 3.60 -0.83% sync_test.BenchmarkMutexUncontended-16 2.38 2.49 +4.62% sync_test.BenchmarkMutex 25.00 26.40 +5.60% sync_test.BenchmarkMutex-2 231.00 49.00 -78.79% sync_test.BenchmarkMutex-4 259.00 114.00 -55.98% sync_test.BenchmarkMutex-8 641.00 110.00 -82.84% sync_test.BenchmarkMutex-16 1380.00 96.30 -93.02% sync_test.BenchmarkMutexSlack 24.80 26.20 +5.65% sync_test.BenchmarkMutexSlack-2 210.00 106.00 -49.52% sync_test.BenchmarkMutexSlack-4 453.00 119.00 -73.73% sync_test.BenchmarkMutexSlack-8 1024.00 105.00 -89.75% sync_test.BenchmarkMutexSlack-16 1291.00 91.90 -92.88% sync_test.BenchmarkMutexWork 796.00 796.00 +0.00% sync_test.BenchmarkMutexWork-2 399.00 401.00 +0.50% sync_test.BenchmarkMutexWork-4 216.00 212.00 -1.85% sync_test.BenchmarkMutexWork-8 1547.00 196.00 -87.33% sync_test.BenchmarkMutexWork-16 2754.00 287.00 -89.58% sync_test.BenchmarkMutexWorkSlack 792.00 800.00 +1.01% sync_test.BenchmarkMutexWorkSlack-2 430.00 420.00 -2.33% sync_test.BenchmarkMutexWorkSlack-4 467.00 230.00 -50.75% sync_test.BenchmarkMutexWorkSlack-8 1860.00 273.00 -85.32% sync_test.BenchmarkMutexWorkSlack-16 3029.00 294.00 -90.29% R=rsc CC=golang-dev https://golang.org/cl/4631075 |
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This is the source code repository for the Go programming language.
For documentation about how to install and use Go,
visit http://golang.org/ or load doc/install.html in your web browser.
After installing Go, you can view a nicely formatted
doc/install.html by running godoc --http=:6060
and then visiting http://localhost:6060/doc/install.html.
Unless otherwise noted, the Go source files are distributed
under the BSD-style license found in the LICENSE file.
--
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.