Adjust histograms to get better data for latency experiments...

base/histogram.h

 // Copyright (c) 2006-2008 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.
 
 // Histogram is an object that aggregates statistics, and can summarize them in
 // various forms, including ASCII graphical, HTML, and numerically (as a
 // vector of numbers corresponding to each of the aggregating buckets).
 
 // It supports calls to accumulate either time intervals (which are processed
 // as integral number of milliseconds), or arbitrary integral units.
@@ skipping 84 matching lines @@
 #endif  // NDEBUG
 
 //------------------------------------------------------------------------------
 // The following macros provide typical usage scenarios for callers that wish
 // to record histogram data, and have the data submitted/uploaded via UMA.
 // Not all systems support such UMA, but if they do, the following macros
 // should work with the service.
 
 static const int kUmaTargetedHistogramFlag = 0x1;
 
 #define UMA_HISTOGRAM_TIMES(name, sample) do { \

[Lincoln, 2008/11/24 17:31:42]

If the other macro describes a "medium" histogram entry, then what size should
this macro have?

     static Histogram counter((name), base::TimeDelta::FromMilliseconds(1), \
                              base::TimeDelta::FromSeconds(10), 50); \
     counter.SetFlags(kUmaTargetedHistogramFlag); \
     counter.AddTime(sample); \
   } while (0)
 
+#define UMA_HISTOGRAM_MEDIUM_TIMES(name, sample) do { \
+    static Histogram counter((name), base::TimeDelta::FromMilliseconds(10), \
+                             base::TimeDelta::FromMinutes(3), 50); \
+    counter.SetFlags(kUmaTargetedHistogramFlag); \
+    counter.AddTime(sample); \
+  } while (0)
+
 // Use this macro when times can routinely be much longer than 10 seconds.
 #define UMA_HISTOGRAM_LONG_TIMES(name, sample) do { \
     static Histogram counter((name), base::TimeDelta::FromMilliseconds(1), \
                              base::TimeDelta::FromHours(1), 50); \
     counter.SetFlags(kUmaTargetedHistogramFlag); \
     counter.AddTime(sample); \
   } while (0)
 
 #define UMA_HISTOGRAM_COUNTS(name, sample) do { \
     static Histogram counter((name), 1, 1000000, 50); \
@@ skipping 70 matching lines @@
   Histogram(const wchar_t* name, Sample minimum,
             Sample maximum, size_t bucket_count);
   Histogram(const wchar_t* name, base::TimeDelta minimum,
             base::TimeDelta maximum, size_t bucket_count);
   virtual ~Histogram();
 
   // Hooks to override stats counter methods.  This ensures that we gather all
   // input the stats counter sees.
   virtual void Add(int value);
 
-  // The following methods provide a graphical histogram displays.
+  // The following methods provide graphical histogram displays.
   void WriteHTMLGraph(std::string* output) const;
   void WriteAscii(bool graph_it, const std::string& newline,
                   std::string* output) const;
 
   // Support generic flagging of Histograms.
   // 0x1 Currently used to mark this histogram to be recorded by UMA..
   // 0x8000 means print ranges in hex.
   void SetFlags(int flags) { flags_ |= flags; }
   void ClearFlags(int flags) { flags_ &= ~flags; }
   int flags() const { return flags_; }
@@ skipping 223 matching lines @@
   static Lock* lock_;
 
   // Dump all known histograms to log.
   static bool dump_on_exit_;
 
   DISALLOW_EVIL_CONSTRUCTORS(StatisticsRecorder);
 };
 
 #endif  // BASE_HISTOGRAM_H__