github.com/peggyl/go@v0.0.0-20151008231540-ae315999c2d5/src/runtime/runtime.go (about)

     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 _ "unsafe" // for go:linkname
     8  
     9  //go:generate go run wincallback.go
    10  //go:generate go run mkduff.go
    11  //go:generate go run mkfastlog2table.go
    12  
    13  var ticks struct {
    14  	lock mutex
    15  	pad  uint32 // ensure 8-byte alignment of val on 386
    16  	val  uint64
    17  }
    18  
    19  var tls0 [8]uintptr // available storage for m0's TLS; not necessarily used; opaque to GC
    20  
    21  // Note: Called by runtime/pprof in addition to runtime code.
    22  func tickspersecond() int64 {
    23  	r := int64(atomicload64(&ticks.val))
    24  	if r != 0 {
    25  		return r
    26  	}
    27  	lock(&ticks.lock)
    28  	r = int64(ticks.val)
    29  	if r == 0 {
    30  		t0 := nanotime()
    31  		c0 := cputicks()
    32  		usleep(100 * 1000)
    33  		t1 := nanotime()
    34  		c1 := cputicks()
    35  		if t1 == t0 {
    36  			t1++
    37  		}
    38  		r = (c1 - c0) * 1000 * 1000 * 1000 / (t1 - t0)
    39  		if r == 0 {
    40  			r++
    41  		}
    42  		atomicstore64(&ticks.val, uint64(r))
    43  	}
    44  	unlock(&ticks.lock)
    45  	return r
    46  }
    47  
    48  var envs []string
    49  var argslice []string
    50  
    51  //go:linkname syscall_runtime_envs syscall.runtime_envs
    52  func syscall_runtime_envs() []string { return append([]string{}, envs...) }
    53  
    54  //go:linkname os_runtime_args os.runtime_args
    55  func os_runtime_args() []string { return append([]string{}, argslice...) }