From c007ce824d9a4fccb148f9204e04c23ed2984b71 Mon Sep 17 00:00:00 2001
From: Russ Cox <rsc@golang.org>
Date: Mon, 8 Sep 2014 00:08:51 -0400
Subject: build: move package sources from src/pkg to src

Preparation was in CL 134570043.
This CL contains only the effect of 'hg mv src/pkg/* src'.
For more about the move, see golang.org/s/go14nopkg.
---
 src/runtime/runtime.go | 37 +++++++++++++++++++++++++++++++++++++
 1 file changed, 37 insertions(+)
 create mode 100644 src/runtime/runtime.go

(limited to 'src/runtime/runtime.go')

diff --git a/src/runtime/runtime.go b/src/runtime/runtime.go
new file mode 100644
index 0000000000..d5b31559a2
--- /dev/null
+++ b/src/runtime/runtime.go
@@ -0,0 +1,37 @@
+// 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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