go - The Go programming language

Age	Commit message (Collapse)	Author
2018-03-27	runtime: use vDSO for clock_gettime on linux/arm64	Meng Zhuo
	Use the __vdso_clock_gettime fast path via the vDSO on linux/arm64 to speed up nanotime and walltime. This results in the following performance improvement for time.Now on Cavium ThunderX: name old time/op new time/op delta TimeNow 442ns ± 0% 163ns ± 0% -63.16% (p=0.000 n=10+10) And benchmarks on VDSO BenchmarkClockVDSOAndFallbackPaths/vDSO 10000000 166 ns/op BenchmarkClockVDSOAndFallbackPaths/Fallback 3000000 456 ns/op Change-Id: I326118c6dff865eaa0569fc45d1fc1ff95cb74f6 Reviewed-on: https://go-review.googlesource.com/99855 Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com> Run-TryBot: Ian Lance Taylor <iant@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Ian Lance Taylor <iant@golang.org>
2018-03-05	runtime: rename vdso symbols to use camel case	Ian Lance Taylor
	This was originally C code using names with underscores, which were retained when the code was rewritten into Go. Change the code to use Go-like camel case names. The names that come from the ELF ABI are left unchanged. Change-Id: I181bc5dd81284c07bc67b7df4635f4734b41d646 Reviewed-on: https://go-review.googlesource.com/98520 Run-TryBot: Ian Lance Taylor <iant@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Tobias Klauser <tobias.klauser@gmail.com> Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2018-02-15	runtime: move ELF structure definitions into own files	Tobias Klauser
	Move the ELF32 and ELF64 structure definitions into their own files so they can be reused when vDSO support is added for other architectures. Change-Id: Id0171b4e5cea4add8635743c881e3bf3469597af Reviewed-on: https://go-review.googlesource.com/93995 Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Austin Clements <austin@google.com>
2017-10-13	runtime: use vDSO on linux/386 to improve time.Now performance	Frank Somers
	This change adds support for accelerating time.Now by using the __vdso_clock_gettime fast-path via the vDSO on linux/386 if it is available. When the vDSO path to the clocks is available, it is typically 5x-10x faster than the syscall path (see benchmark extract below). Two such calls are made for each time.Now() call on most platforms as of go 1.9. - Add vdso_linux_386.go, containing the ELF32 definitions for use by vdso_linux.go, the maximum array size, and the symbols to be located in the vDSO. - Modify runtime.walltime and runtime.nanotime to check for and use the vDSO fast-path if available, or fall back to the existing syscall path. - Reduce the stack reservations for runtime.walltime and runtime.monotime from 32 to 16 bytes. It appears the syscall path actually only needed 8 bytes, but 16 is now needed to cover the syscall and vDSO paths. - Remove clearing DX from the syscall paths as clock_gettime only takes 2 args (BX, CX in syscall calling convention), so there should be no need to clear DX. The included BenchmarkTimeNow was run with -cpu=1 -count=20 on an "Intel(R) Celeron(R) CPU J1900 @ 1.99GHz", comparing released go 1.9.1 vs this change. This shows a gain in performance on linux/386 (6.89x), and that no regression occurred on linux/amd64 due to this change. Kernel: linux/i686, GOOS=linux GOARCH=386 name old time/op new time/op delta TimeNow 978ns ± 0% 142ns ± 0% -85.48% (p=0.000 n=16+20) Kernel: linux/x86_64, GOOS=linux GOARCH=amd64 name old time/op new time/op delta TimeNow 125ns ± 0% 125ns ± 0% ~ (all equal) Gains are more dramatic in virtualized environments, presumably due to the overhead of virtualizing the syscall. Fixes #22190 Change-Id: I2f83ce60cb1b8b310c9ced0706bb463c1b3aedf8 Reviewed-on: https://go-review.googlesource.com/69390 Run-TryBot: Ian Lance Taylor <iant@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Ian Lance Taylor <iant@golang.org>