mirror of
https://github.com/golang/go
synced 2024-10-07 09:21:23 -06:00
38 lines
710 B
Go
38 lines
710 B
Go
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// Copyright 2009 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package runtime
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var ticks struct {
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lock mutex
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val uint64
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}
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// Note: Called by runtime/pprof in addition to runtime code.
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func tickspersecond() int64 {
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r := int64(atomicload64(&ticks.val))
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if r != 0 {
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return r
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}
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lock(&ticks.lock)
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r = int64(ticks.val)
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if r == 0 {
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t0 := nanotime()
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c0 := cputicks()
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usleep(100 * 1000)
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t1 := nanotime()
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c1 := cputicks()
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if t1 == t0 {
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t1++
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}
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r = (c1 - c0) * 1000 * 1000 * 1000 / (t1 - t0)
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if r == 0 {
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r++
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}
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atomicstore64(&ticks.val, uint64(r))
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}
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unlock(&ticks.lock)
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return r
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}
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