123f7dd3e1
Apparently, the signal handling code path in darwin kernel leaves the upper bits of Y registers in a dirty state, which causes many SSE operations (128-bit and narrower) become much slower. Clear the upper bits to get to a clean state. We do it at the entry of asyncPreempt, which is immediately following exiting from the kernel's signal handling code, if we actually injected a call. It does not cover other exits where we don't inject a call, e.g. failed preemption, profiling signal, or other async signals. But it does cover an important use case of async signals, preempting a tight numerical loop, which we introduced in this cycle. Running the benchmark in issue #37174: name old time/op new time/op delta Fast-8 90.0ns ± 1% 46.8ns ± 3% -47.97% (p=0.000 n=10+10) Slow-8 188ns ± 5% 49ns ± 1% -73.82% (p=0.000 n=10+9) There is no more slowdown due to preemption signals. For #37174. Change-Id: I8b83d083fade1cabbda09b4bc25ccbadafaf7605 Reviewed-on: https://go-review.googlesource.com/c/go/+/219131 Run-TryBot: Cherry Zhang <cherryyz@google.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Keith Randall <khr@golang.org> |
||
|---|---|---|
| .github | ||
| api | ||
| doc | ||
| lib/time | ||
| misc | ||
| src | ||
| test | ||
| .gitattributes | ||
| .gitignore | ||
| AUTHORS | ||
| CONTRIBUTING.md | ||
| CONTRIBUTORS | ||
| LICENSE | ||
| PATENTS | ||
| README.md | ||
| SECURITY.md | ||
| favicon.ico | ||
| robots.txt | ||
README.md
The Go Programming Language
Go is an open source programming language that makes it easy to build simple, reliable, and efficient software.
Gopher image by Renee French, licensed under Creative Commons 3.0 Attributions license.
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.
Download and Install
Binary Distributions
Official binary distributions are available at https://golang.org/dl/.
After downloading a binary release, visit https://golang.org/doc/install or load doc/install.html in your web browser for installation instructions.
Install From Source
If a binary distribution is not available for your combination of operating system and architecture, visit https://golang.org/doc/install/source or load doc/install-source.html in your web browser for source installation instructions.
Contributing
Go is the work of thousands of contributors. We appreciate your help!
To contribute, please read the contribution guidelines: https://golang.org/doc/contribute.html
Note that the Go project uses 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.