9e6b79a5df
This greatly improves the latency of starting a child process when the Go process is using a lot of memory. Even though the kernel uses copy-on-write, preparation for that can take up to several 100ms under certain conditions. All other goroutines are suspended while starting a subprocess so this latency directly affects total throughput. With CLONE_VM the child process shares the same memory with the parent process. On its own this would lead to conflicting use of the same memory, so CLONE_VFORK is used to suspend the parent process until the child releases the memory when switching to to the new program binary via the exec syscall. When the parent process continues to run, one has to consider the changes to memory that the child process did, namely the return address of the syscall function needs to be restored from a register. A simple benchmark has shown a difference in latency of 16ms vs. 0.5ms at 10GB memory usage. However, much higher latencies of several 100ms have been observed in real world scenarios. For more information see comments on #5838. Fixes #5838 Change-Id: I6377d7bd8dcd00c85ca0c52b6683e70ce2174ba6 Reviewed-on: https://go-review.googlesource.com/37439 Reviewed-by: Ian Lance Taylor <iant@golang.org> Run-TryBot: Ian Lance Taylor <iant@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org> |
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README.md
The Go Programming Language
Go is an open source programming language that makes it easy to build simple, reliable, and efficient software.
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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.
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Install From Source
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Contributing
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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.