441502154f
The endcgo function call is currently deferred in case a cgo callback into Go panics and unwinds through cgocall. Typical cgo calls do not have callbacks into Go, and even fewer panic, so we pay the cost of this defer for no typical benefit. Amazingly, there is another defer on the cgocallback path also used to cleanup in case the Go code called by cgo panics. This CL folds the first defer into the second, to reduce the cost of typical cgo calls. This reduces the overhead for a no-op cgo call significantly: name old time/op new time/op delta CgoNoop-8 93.5ns ± 0% 51.1ns ± 1% -45.34% (p=0.016 n=4+5) The total effect between Go 1.7 and 1.8 is even greater, as CL 29656 reduced the cost of defer recently. Hopefully a future Go release will drop the cost of defer to nothing, making this optimization unnecessary. But until then, this is nice. Change-Id: Id1a5648f687a87001d95bec6842e4054bd20ee4f Reviewed-on: https://go-review.googlesource.com/30080 Run-TryBot: David Crawshaw <crawshaw@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Ian Lance Taylor <iant@golang.org> |
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The Go Programming Language
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.
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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 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.