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go/src/runtime/unaligned1.go

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runtime: a better fallback hash For arm and powerpc, as well as x86 without aes instructions. Contains a mixture of ideas from cityhash and xxhash. Compared to our old fallback on ARM, it's ~no slower on small objects and up to ~50% faster on large objects. More importantly, it is a much better hash function and thus has less chance of bad behavior. Fixes #8737 benchmark old ns/op new ns/op delta BenchmarkHash5 173 181 +4.62% BenchmarkHash16 252 212 -15.87% BenchmarkHash64 575 419 -27.13% BenchmarkHash1024 7173 3995 -44.31% BenchmarkHash65536 516940 313173 -39.42% BenchmarkHashStringSpeed 300 279 -7.00% BenchmarkHashBytesSpeed 478 424 -11.30% BenchmarkHashInt32Speed 217 207 -4.61% BenchmarkHashInt64Speed 262 231 -11.83% BenchmarkHashStringArraySpeed 609 631 +3.61% Change-Id: I0a9335028f32b10ad484966e3019987973afd3eb Reviewed-on: https://go-review.googlesource.com/1360 Reviewed-by: Russ Cox <rsc@golang.org>
2014-12-10 18:02:58 -07:00
// Copyright 2014 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
runtime: add support for linux/arm64 Change-Id: Ibda6a5bedaff57fd161d63fc04ad260931d34413 Reviewed-on: https://go-review.googlesource.com/7142 Reviewed-by: Russ Cox <rsc@golang.org>
2015-03-08 07:20:20 -06:00
// +build 386 amd64 amd64p32 arm64
runtime: a better fallback hash For arm and powerpc, as well as x86 without aes instructions. Contains a mixture of ideas from cityhash and xxhash. Compared to our old fallback on ARM, it's ~no slower on small objects and up to ~50% faster on large objects. More importantly, it is a much better hash function and thus has less chance of bad behavior. Fixes #8737 benchmark old ns/op new ns/op delta BenchmarkHash5 173 181 +4.62% BenchmarkHash16 252 212 -15.87% BenchmarkHash64 575 419 -27.13% BenchmarkHash1024 7173 3995 -44.31% BenchmarkHash65536 516940 313173 -39.42% BenchmarkHashStringSpeed 300 279 -7.00% BenchmarkHashBytesSpeed 478 424 -11.30% BenchmarkHashInt32Speed 217 207 -4.61% BenchmarkHashInt64Speed 262 231 -11.83% BenchmarkHashStringArraySpeed 609 631 +3.61% Change-Id: I0a9335028f32b10ad484966e3019987973afd3eb Reviewed-on: https://go-review.googlesource.com/1360 Reviewed-by: Russ Cox <rsc@golang.org>
2014-12-10 18:02:58 -07:00
package runtime
import "unsafe"
func readUnaligned32(p unsafe.Pointer) uint32 {
return *(*uint32)(p)
}
func readUnaligned64(p unsafe.Pointer) uint64 {
return *(*uint64)(p)
}
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