[dev.link] all: merge branch 'master' into dev.linkdev.link

Clean merge.

Change-Id: Ia7b2808bc649790198d34c226a61d9e569084dc5

1 files changed, 37 insertions, 0 deletions

diff --git a/src/runtime/metrics/sample.go b/src/runtime/metrics/sample.go
new file mode 100644
index 0000000000..b4b0979aa6
--- /dev/null
+++ b/src/runtime/metrics/sample.go
@@ -0,0 +1,37 @@
+// Copyright 2020 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 metrics
+
+import (
+	_ "runtime" // depends on the runtime via a linkname'd function
+	"unsafe"
+)
+
+// Sample captures a single metric sample.
+type Sample struct {
+	// Name is the name of the metric sampled.
+	//
+	// It must correspond to a name in one of the metric descriptions
+	// returned by Descriptions.
+	Name string
+
+	// Value is the value of the metric sample.
+	Value Value
+}
+
+// Implemented in the runtime.
+func runtime_readMetrics(unsafe.Pointer, int, int)
+
+// Read populates each Value field in the given slice of metric samples.
+//
+// Desired metrics should be present in the slice with the appropriate name.
+// The user of this API is encouraged to re-use the same slice between calls.
+//
+// Metric values with names not appearing in the value returned by Descriptions
+// will have the value populated as KindBad to indicate that the name is
+// unknown.
+func Read(m []Sample) {
+	runtime_readMetrics(unsafe.Pointer(&m[0]), len(m), cap(m))
+}