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ea59ebd338
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>
22 lines
670 B
Go
22 lines
670 B
Go
// Copyright 2018 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package runtime
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const (
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// vdsoArrayMax is the byte-size of a maximally sized array on this architecture.
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// See cmd/compile/internal/arm64/galign.go arch.MAXWIDTH initialization.
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vdsoArrayMax = 1<<50 - 1
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)
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// key and version at man 7 vdso : aarch64
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var vdsoLinuxVersion = vdsoVersionKey{"LINUX_2.6.39", 0x75fcb89}
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var vdsoSymbolKeys = []vdsoSymbolKey{
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{"__kernel_clock_gettime", 0xd35ec75, 0x6e43a318, &vdsoClockgettimeSym},
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}
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// initialize to fall back to syscall
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var vdsoClockgettimeSym uintptr = 0
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