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

Clean merge.

Change-Id: Ia7b2808bc649790198d34c226a61d9e569084dc5

1 files changed, 30 insertions, 0 deletions

diff --git a/src/runtime/metrics/histogram.go b/src/runtime/metrics/histogram.go
new file mode 100644
index 0000000000..e1364e1e26
--- /dev/null
+++ b/src/runtime/metrics/histogram.go
@@ -0,0 +1,30 @@
+// 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
+
+// Float64Histogram represents a distribution of float64 values.
+type Float64Histogram struct {
+	// Counts contains the weights for each histogram bucket. The length of
+	// Counts is equal to the length of Buckets (in the metric description)
+	// plus one to account for the implicit minimum bucket.
+	//
+	// Given N buckets, the following is the mathematical relationship between
+	// Counts and Buckets.
+	// count[0] is the weight of the range (-inf, bucket[0])
+	// count[n] is the weight of the range [bucket[n], bucket[n+1]), for 0 < n < N-1
+	// count[N-1] is the weight of the range [bucket[N-1], inf)
+	Counts []uint64
+
+	// Buckets contains the boundaries between histogram buckets, in increasing order.
+	//
+	// Because this slice contains boundaries, there are len(Buckets)+1 counts:
+	// a count for all values less than the first boundary, a count covering each
+	// [slice[i], slice[i+1]) interval, and a count for all values greater than or
+	// equal to the last boundary.
+	//
+	// For a given metric name, the value of Buckets is guaranteed not to change
+	// between calls until program exit.
+	Buckets []float64
+}