runtime.go

     1  // Copyright 2009 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package runtime
     6  
     7  import (
     8  	"runtime/internal/atomic"
     9  	_ "unsafe" // for go:linkname
    10  )
    11  
    12  //go:generate go run wincallback.go
    13  //go:generate go run mkduff.go
    14  //go:generate go run mkfastlog2table.go
    15  
    16  var ticks struct {
    17  	lock mutex
    18  	pad  uint32 // ensure 8-byte alignment of val on 386
    19  	val  uint64
    20  }
    21  
    22  // Note: Called by runtime/pprof in addition to runtime code.
    23  func tickspersecond() int64 {
    24  	r := int64(atomic.Load64(&ticks.val))
    25  	if r != 0 {
    26  		return r
    27  	}
    28  	lock(&ticks.lock)
    29  	r = int64(ticks.val)
    30  	if r == 0 {
    31  		t0 := nanotime()
    32  		c0 := cputicks()
    33  		usleep(100 * 1000)
    34  		t1 := nanotime()
    35  		c1 := cputicks()
    36  		if t1 == t0 {
    37  			t1++
    38  		}
    39  		r = (c1 - c0) * 1000 * 1000 * 1000 / (t1 - t0)
    40  		if r == 0 {
    41  			r++
    42  		}
    43  		atomic.Store64(&ticks.val, uint64(r))
    44  	}
    45  	unlock(&ticks.lock)
    46  	return r
    47  }
    48  
    49  var envs []string
    50  var argslice []string
    51  
    52  //go:linkname syscall_runtime_envs syscall.runtime_envs
    53  func syscall_runtime_envs() []string { return append([]string{}, envs...) }
    54  
    55  //go:linkname syscall_Getpagesize syscall.Getpagesize
    56  func syscall_Getpagesize() int { return int(physPageSize) }
    57  
    58  //go:linkname os_runtime_args os.runtime_args
    59  func os_runtime_args() []string { return append([]string{}, argslice...) }
    60  
    61  //go:linkname syscall_Exit syscall.Exit
    62  //go:nosplit
    63  func syscall_Exit(code int) {
    64  	exit(int32(code))
    65  }
    66
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