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go/src/runtime/runtime.go
Austin Clements 1b9499b069 syscall: make Getpagesize return page size from runtime
syscall.Getpagesize currently returns hard-coded page sizes on all
architectures (some of which are probably always wrong, and some of
which are definitely not always right). The runtime now has this
information, queried from the OS during runtime init, so make
syscall.Getpagesize return the page size that the runtime knows.

Updates #10180.

Change-Id: I4daa6fbc61a2193eb8fa9e7878960971205ac346
Reviewed-on: https://go-review.googlesource.com/25051
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2016-09-06 21:05:55 +00:00

60 lines
1.3 KiB
Go

// Copyright 2009 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.
package runtime
import (
"runtime/internal/atomic"
_ "unsafe" // for go:linkname
)
//go:generate go run wincallback.go
//go:generate go run mkduff.go
//go:generate go run mkfastlog2table.go
var ticks struct {
lock mutex
pad uint32 // ensure 8-byte alignment of val on 386
val uint64
}
// Note: Called by runtime/pprof in addition to runtime code.
func tickspersecond() int64 {
r := int64(atomic.Load64(&ticks.val))
if r != 0 {
return r
}
lock(&ticks.lock)
r = int64(ticks.val)
if r == 0 {
t0 := nanotime()
c0 := cputicks()
usleep(100 * 1000)
t1 := nanotime()
c1 := cputicks()
if t1 == t0 {
t1++
}
r = (c1 - c0) * 1000 * 1000 * 1000 / (t1 - t0)
if r == 0 {
r++
}
atomic.Store64(&ticks.val, uint64(r))
}
unlock(&ticks.lock)
return r
}
var envs []string
var argslice []string
//go:linkname syscall_runtime_envs syscall.runtime_envs
func syscall_runtime_envs() []string { return append([]string{}, envs...) }
//go:linkname syscall_Getpagesize syscall.Getpagesize
func syscall_Getpagesize() int { return int(physPageSize) }
//go:linkname os_runtime_args os.runtime_args
func os_runtime_args() []string { return append([]string{}, argslice...) }