first pass histogram shrink

base/metrics/histogram.h

 // Copyright (c) 2012 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 117 matching lines @@
           reinterpret_cast<base::subtle::AtomicWord>(histogram_pointer));
     }
 
     // Ensure calling contract is upheld, and the name does NOT vary.
     DCHECK(histogram_pointer->histogram_name() == constant_histogram_name);
 
     histogram_pointer->Add(sample);
   } while (0);
 */
 
+#define SMALL_STATIC_HISTOGRAM_POINTER_BLOCK(constant_histogram_name, \
+  histogram_add_method_invocation, \
+  histogram_factory_get_name, \
+                                             ...) \
+  do { \
+    static base::subtle::AtomicWord atomic_histogram_pointer = 0; \
+    base::HistogramBase* histogram_pointer( \
+        reinterpret_cast<base::HistogramBase*>( \
+            base::subtle::Acquire_Load(&atomic_histogram_pointer))); \
+    if (!histogram_pointer) { \
+      histogram_pointer = \
+          histogram_factory_get_name##AndAtomicRelease(&atomic_histogram_pointer, \
+                                                       __VA_ARGS__); \
+    } \
+    DCHECK_EQ(histogram_pointer->histogram_name(), \
+              std::string(constant_histogram_name));    \
+    histogram_pointer->histogram_add_method_invocation; \
+  } while (0)
+
 // The above pattern is repeated in several macros.  The only elements that
 // vary are the invocation of the Add(sample) vs AddTime(sample), and the choice
 // of which FactoryGet method to use.  The different FactoryGet methods have
 // various argument lists, so the function with its argument list is provided as
 // a macro argument here.  The name is only used in a DCHECK, to assure that
 // callers don't try to vary the name of the histogram (which would tend to be
 // ignored by the one-time initialization of the histogtram_pointer).
 #define STATIC_HISTOGRAM_POINTER_BLOCK(constant_histogram_name, \
                                        histogram_add_method_invocation, \
                                        histogram_factory_get_invocation) \
   do { \
     static base::subtle::AtomicWord atomic_histogram_pointer = 0; \
     base::HistogramBase* histogram_pointer( \
         reinterpret_cast<base::HistogramBase*>( \
             base::subtle::Acquire_Load(&atomic_histogram_pointer))); \
     if (!histogram_pointer) { \
       histogram_pointer = histogram_factory_get_invocation; \
-      base::subtle::Release_Store(&atomic_histogram_pointer, \
+      base::subtle::NoBarrier_Store(&atomic_histogram_pointer, \
           reinterpret_cast<base::subtle::AtomicWord>(histogram_pointer)); \
     } \
     DCHECK_EQ(histogram_pointer->histogram_name(), \
               std::string(constant_histogram_name)); \
     histogram_pointer->histogram_add_method_invocation; \
   } while (0)
 
 
 //------------------------------------------------------------------------------
 // Provide easy general purpose histogram in a macro, just like stats counters.
 // The first four macros use 50 buckets.
 
 #define HISTOGRAM_TIMES(name, sample) HISTOGRAM_CUSTOM_TIMES( \
     name, sample, base::TimeDelta::FromMilliseconds(1), \
     base::TimeDelta::FromSeconds(10), 50)
 
 // For folks that need real specific times, use this to select a precise range
 // of times you want plotted, and the number of buckets you want used.
-#define HISTOGRAM_CUSTOM_TIMES(name, sample, min, max, bucket_count) \
-    STATIC_HISTOGRAM_POINTER_BLOCK(name, AddTime(sample), \
+#if 1
+#define HISTOGRAM_CUSTOM_TIMES(name, sample, min, max, bucket_count)  \
+    STATIC_HISTOGRAM_POINTER_BLOCK(name, AddTime(sample),             \
         base::Histogram::FactoryTimeGet(name, min, max, bucket_count, \
                                         base::HistogramBase::kNoFlags))
+#else
+#define HISTOGRAM_CUSTOM_TIMES(name, sample, min, max, bucket_count) \
+    SMALL_STATIC_HISTOGRAM_POINTER_BLOCK( \
+        name, AddTime(sample), base::Histogram::FactoryTimeGet, \
+        name, min, max, bucket_count, base::HistogramBase::kNoFlags)
+#endif
 
 #define HISTOGRAM_COUNTS(name, sample) HISTOGRAM_CUSTOM_COUNTS( \
     name, sample, 1, 1000000, 50)
 
 #define HISTOGRAM_COUNTS_100(name, sample) HISTOGRAM_CUSTOM_COUNTS( \
     name, sample, 1, 100, 50)
 
 #define HISTOGRAM_COUNTS_10000(name, sample) HISTOGRAM_CUSTOM_COUNTS( \
     name, sample, 1, 10000, 50)
 
@@ skipping 212 matching lines @@
   static HistogramBase* FactoryGet(const std::string& name,
                                    Sample minimum,
                                    Sample maximum,
                                    size_t bucket_count,
                                    int32 flags);
   static HistogramBase* FactoryTimeGet(const std::string& name,
                                        base::TimeDelta minimum,
                                        base::TimeDelta maximum,
                                        size_t bucket_count,
                                        int32 flags);
+  static HistogramBase* FactoryTimeGetAndAtomicRelease(
+      base::subtle::AtomicWord* atomic_histogram_pointer,
+      const std::string& name,
+      base::TimeDelta minimum,
+      base::TimeDelta maximum,
+      size_t bucket_count,
+      int32 flags);
 
   // Time call for use with DHISTOGRAM*.
   // Returns TimeTicks::Now() in debug and TimeTicks() in release build.
   static TimeTicks DebugNow();
 
   static void InitializeBucketRanges(Sample minimum,
                                      Sample maximum,
                                      BucketRanges* ranges);
 
   // This constant if for FindCorruption. Since snapshots of histograms are
@@ skipping 264 matching lines @@
   static bool ValidateCustomRanges(const std::vector<Sample>& custom_ranges);
   static BucketRanges* CreateBucketRangesFromCustomRanges(
       const std::vector<Sample>& custom_ranges);
 
   DISALLOW_COPY_AND_ASSIGN(CustomHistogram);
 };
 
 }  // namespace base
 
 #endif  // BASE_METRICS_HISTOGRAM_H_