Show max latency on client's status bar

remoting/base/running_samples.cc

Index: remoting/base/running_samples.cc
diff --git a/remoting/base/running_average.cc b/remoting/base/running_samples.cc
similarity index 50%
rename from remoting/base/running_average.cc
rename to remoting/base/running_samples.cc
index 5e24c0de3a95672c1e4f8d4c5b67cf5b11db81ba..352d6a6fe4ce38cd767df9a1f24f6e100d7878e7 100644
--- a/remoting/base/running_average.cc
+++ b/remoting/base/running_samples.cc
@@ -1,22 +1,23 @@
-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "remoting/base/running_average.h"
+#include "remoting/base/running_samples.h"
+
+#include <algorithm>
 
 #include "base/logging.h"
 
 namespace remoting {
 
-RunningAverage::RunningAverage(int window_size)
-    : window_size_(window_size),
-      sum_(0) {
+RunningSamples::RunningSamples(int window_size)
+    : window_size_(window_size) {
   DCHECK_GT(window_size, 0);
 }
 
-RunningAverage::~RunningAverage() {}
+RunningSamples::~RunningSamples() {}
 
-void RunningAverage::Record(int64_t value) {
+void RunningSamples::Record(int64_t value) {
   DCHECK(thread_checker_.CalledOnValidThread());
 
   data_points_.push_back(value);
@@ -28,7 +29,7 @@ void RunningAverage::Record(int64_t value) {
   }
 }
 
-double RunningAverage::Average() {
+double RunningSamples::Average() const {
   DCHECK(thread_checker_.CalledOnValidThread());
 
   if (data_points_.empty())
@@ -36,4 +37,14 @@ double RunningAverage::Average() {
   return static_cast<double>(sum_) / data_points_.size();
 }
 
+int64_t RunningSamples::Max() const {
+  DCHECK(thread_checker_.CalledOnValidThread());
+
+  if (data_points_.empty())
+    return 0;
+
+  // O(n*w), may be improved.

[Sergey Ulanov, 2016/03/21 19:35:06]

What is w? I don't think you really need this comment. It's obvious it's linear
complexity, but in this case it's not worthwhile to try improving it.

[Yuwei, 2016/03/21 19:59:40]

w just means window size so finding max after having n samples will be O(n*w)...
This is just the possibility of micro-optimization, so I will remove this
comment...

[Sergey Ulanov, 2016/03/21 23:54:52]

Not sure why it's O(n*w) and not O(w). There are less than w elements in
data_points_ and you iterate over them to find the max. I don't see how n play a
part here.

+  return *std::max_element(data_points_.begin(), data_points_.end());
+}
+
 }  // namespace remoting