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// 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
var ticks struct {
lock mutex
val uint64
}
// Note: Called by runtime/pprof in addition to runtime code.
func tickspersecond() int64 {
r := int64(atomicload64(&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++
}
atomicstore64(&ticks.val, uint64(r))
}
unlock(&ticks.lock)
return r
}
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