1 // Copyright 2014 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4 
5 #ifndef BASE_METRICS_HISTOGRAM_MACROS_H_
6 #define BASE_METRICS_HISTOGRAM_MACROS_H_
7 
8 #include "base/atomicops.h"
9 #include "base/logging.h"
10 #include "base/metrics/histogram.h"
11 #include "base/time/time.h"
12 
13 //------------------------------------------------------------------------------
14 // Histograms are often put in areas where they are called many many times, and
15 // performance is critical.  As a result, they are designed to have a very low
16 // recurring cost of executing (adding additional samples).  Toward that end,
17 // the macros declare a static pointer to the histogram in question, and only
18 // take a "slow path" to construct (or find) the histogram on the first run
19 // through the macro.  We leak the histograms at shutdown time so that we don't
20 // have to validate using the pointers at any time during the running of the
21 // process.
22 
23 // The following code is generally what a thread-safe static pointer
24 // initialization looks like for a histogram (after a macro is expanded).  This
25 // sample is an expansion (with comments) of the code for
26 // LOCAL_HISTOGRAM_CUSTOM_COUNTS().
27 
28 /*
29   do {
30     // The pointer's presence indicates the initialization is complete.
31     // Initialization is idempotent, so it can safely be atomically repeated.
32     static base::subtle::AtomicWord atomic_histogram_pointer = 0;
33 
34     // Acquire_Load() ensures that we acquire visibility to the pointed-to data
35     // in the histogram.
36     base::Histogram* histogram_pointer(reinterpret_cast<base::Histogram*>(
37         base::subtle::Acquire_Load(&atomic_histogram_pointer)));
38 
39     if (!histogram_pointer) {
40       // This is the slow path, which will construct OR find the matching
41       // histogram.  FactoryGet includes locks on a global histogram name map
42       // and is completely thread safe.
43       histogram_pointer = base::Histogram::FactoryGet(
44           name, min, max, bucket_count, base::HistogramBase::kNoFlags);
45 
46       // Use Release_Store to ensure that the histogram data is made available
47       // globally before we make the pointer visible.
48       // Several threads may perform this store, but the same value will be
49       // stored in all cases (for a given named/spec'ed histogram).
50       // We could do this without any barrier, since FactoryGet entered and
51       // exited a lock after construction, but this barrier makes things clear.
52       base::subtle::Release_Store(&atomic_histogram_pointer,
53           reinterpret_cast<base::subtle::AtomicWord>(histogram_pointer));
54     }
55 
56     // Ensure calling contract is upheld, and the name does NOT vary.
57     DCHECK(histogram_pointer->histogram_name() == constant_histogram_name);
58 
59     histogram_pointer->Add(sample);
60   } while (0);
61 */
62 
63 // The above pattern is repeated in several macros.  The only elements that
64 // vary are the invocation of the Add(sample) vs AddTime(sample), and the choice
65 // of which FactoryGet method to use.  The different FactoryGet methods have
66 // various argument lists, so the function with its argument list is provided as
67 // a macro argument here.  The name is only used in a DCHECK, to assure that
68 // callers don't try to vary the name of the histogram (which would tend to be
69 // ignored by the one-time initialization of the histogtram_pointer).
70 #define STATIC_HISTOGRAM_POINTER_BLOCK(constant_histogram_name,           \
71                                        histogram_add_method_invocation,   \
72                                        histogram_factory_get_invocation)  \
73   do {                                                                    \
74     static base::subtle::AtomicWord atomic_histogram_pointer = 0;         \
75     base::HistogramBase* histogram_pointer(                               \
76         reinterpret_cast<base::HistogramBase*>(                           \
77             base::subtle::Acquire_Load(&atomic_histogram_pointer)));      \
78     if (!histogram_pointer) {                                             \
79       histogram_pointer = histogram_factory_get_invocation;               \
80       base::subtle::Release_Store(                                        \
81           &atomic_histogram_pointer,                                      \
82           reinterpret_cast<base::subtle::AtomicWord>(histogram_pointer)); \
83     }                                                                     \
84     if (DCHECK_IS_ON())                                                   \
85       histogram_pointer->CheckName(constant_histogram_name);              \
86     histogram_pointer->histogram_add_method_invocation;                   \
87   } while (0)
88 
89 //------------------------------------------------------------------------------
90 // Provide easy general purpose histogram in a macro, just like stats counters.
91 // The first four macros use 50 buckets.
92 
93 #define LOCAL_HISTOGRAM_TIMES(name, sample) LOCAL_HISTOGRAM_CUSTOM_TIMES( \
94     name, sample, base::TimeDelta::FromMilliseconds(1), \
95     base::TimeDelta::FromSeconds(10), 50)
96 
97 // For folks that need real specific times, use this to select a precise range
98 // of times you want plotted, and the number of buckets you want used.
99 #define LOCAL_HISTOGRAM_CUSTOM_TIMES(name, sample, min, max, bucket_count) \
100     STATIC_HISTOGRAM_POINTER_BLOCK(name, AddTime(sample), \
101         base::Histogram::FactoryTimeGet(name, min, max, bucket_count, \
102                                         base::HistogramBase::kNoFlags))
103 
104 #define LOCAL_HISTOGRAM_COUNTS(name, sample) LOCAL_HISTOGRAM_CUSTOM_COUNTS( \
105     name, sample, 1, 1000000, 50)
106 
107 #define LOCAL_HISTOGRAM_COUNTS_100(name, sample) \
108     LOCAL_HISTOGRAM_CUSTOM_COUNTS(name, sample, 1, 100, 50)
109 
110 #define LOCAL_HISTOGRAM_COUNTS_10000(name, sample) \
111     LOCAL_HISTOGRAM_CUSTOM_COUNTS(name, sample, 1, 10000, 50)
112 
113 #define LOCAL_HISTOGRAM_CUSTOM_COUNTS(name, sample, min, max, bucket_count) \
114     STATIC_HISTOGRAM_POINTER_BLOCK(name, Add(sample), \
115         base::Histogram::FactoryGet(name, min, max, bucket_count, \
116                                     base::HistogramBase::kNoFlags))
117 
118 // This is a helper macro used by other macros and shouldn't be used directly.
119 #define HISTOGRAM_ENUMERATION_WITH_FLAG(name, sample, boundary, flag) \
120     STATIC_HISTOGRAM_POINTER_BLOCK(name, Add(sample), \
121         base::LinearHistogram::FactoryGet(name, 1, boundary, boundary + 1, \
122             flag))
123 
124 #define LOCAL_HISTOGRAM_PERCENTAGE(name, under_one_hundred) \
125     LOCAL_HISTOGRAM_ENUMERATION(name, under_one_hundred, 101)
126 
127 #define LOCAL_HISTOGRAM_BOOLEAN(name, sample) \
128     STATIC_HISTOGRAM_POINTER_BLOCK(name, AddBoolean(sample), \
129         base::BooleanHistogram::FactoryGet(name, base::Histogram::kNoFlags))
130 
131 // Support histograming of an enumerated value.  The samples should always be
132 // strictly less than |boundary_value| -- this prevents you from running into
133 // problems down the line if you add additional buckets to the histogram.  Note
134 // also that, despite explicitly setting the minimum bucket value to |1| below,
135 // it is fine for enumerated histograms to be 0-indexed -- this is because
136 // enumerated histograms should never have underflow.
137 #define LOCAL_HISTOGRAM_ENUMERATION(name, sample, boundary_value) \
138     STATIC_HISTOGRAM_POINTER_BLOCK(name, Add(sample), \
139         base::LinearHistogram::FactoryGet(name, 1, boundary_value, \
140             boundary_value + 1, base::HistogramBase::kNoFlags))
141 
142 // Support histograming of an enumerated value. Samples should be one of the
143 // std::vector<int> list provided via |custom_ranges|. See comments above
144 // CustomRanges::FactoryGet about the requirement of |custom_ranges|.
145 // You can use the helper function CustomHistogram::ArrayToCustomRanges to
146 // transform a C-style array of valid sample values to a std::vector<int>.
147 #define LOCAL_HISTOGRAM_CUSTOM_ENUMERATION(name, sample, custom_ranges) \
148     STATIC_HISTOGRAM_POINTER_BLOCK(name, Add(sample), \
149         base::CustomHistogram::FactoryGet(name, custom_ranges, \
150                                           base::HistogramBase::kNoFlags))
151 
152 #define LOCAL_HISTOGRAM_MEMORY_KB(name, sample) LOCAL_HISTOGRAM_CUSTOM_COUNTS( \
153     name, sample, 1000, 500000, 50)
154 
155 //------------------------------------------------------------------------------
156 // The following macros provide typical usage scenarios for callers that wish
157 // to record histogram data, and have the data submitted/uploaded via UMA.
158 // Not all systems support such UMA, but if they do, the following macros
159 // should work with the service.
160 
161 #define UMA_HISTOGRAM_TIMES(name, sample) UMA_HISTOGRAM_CUSTOM_TIMES( \
162     name, sample, base::TimeDelta::FromMilliseconds(1), \
163     base::TimeDelta::FromSeconds(10), 50)
164 
165 #define UMA_HISTOGRAM_MEDIUM_TIMES(name, sample) UMA_HISTOGRAM_CUSTOM_TIMES( \
166     name, sample, base::TimeDelta::FromMilliseconds(10), \
167     base::TimeDelta::FromMinutes(3), 50)
168 
169 // Use this macro when times can routinely be much longer than 10 seconds.
170 #define UMA_HISTOGRAM_LONG_TIMES(name, sample) UMA_HISTOGRAM_CUSTOM_TIMES( \
171     name, sample, base::TimeDelta::FromMilliseconds(1), \
172     base::TimeDelta::FromHours(1), 50)
173 
174 // Use this macro when times can routinely be much longer than 10 seconds and
175 // you want 100 buckets.
176 #define UMA_HISTOGRAM_LONG_TIMES_100(name, sample) UMA_HISTOGRAM_CUSTOM_TIMES( \
177     name, sample, base::TimeDelta::FromMilliseconds(1), \
178     base::TimeDelta::FromHours(1), 100)
179 
180 #define UMA_HISTOGRAM_CUSTOM_TIMES(name, sample, min, max, bucket_count) \
181     STATIC_HISTOGRAM_POINTER_BLOCK(name, AddTime(sample), \
182         base::Histogram::FactoryTimeGet(name, min, max, bucket_count, \
183             base::HistogramBase::kUmaTargetedHistogramFlag))
184 
185 #define UMA_HISTOGRAM_COUNTS(name, sample) UMA_HISTOGRAM_CUSTOM_COUNTS( \
186     name, sample, 1, 1000000, 50)
187 
188 #define UMA_HISTOGRAM_COUNTS_100(name, sample) UMA_HISTOGRAM_CUSTOM_COUNTS( \
189     name, sample, 1, 100, 50)
190 
191 #define UMA_HISTOGRAM_COUNTS_1000(name, sample) UMA_HISTOGRAM_CUSTOM_COUNTS( \
192     name, sample, 1, 1000, 50)
193 
194 #define UMA_HISTOGRAM_COUNTS_10000(name, sample) UMA_HISTOGRAM_CUSTOM_COUNTS( \
195     name, sample, 1, 10000, 50)
196 
197 #define UMA_HISTOGRAM_CUSTOM_COUNTS(name, sample, min, max, bucket_count) \
198     STATIC_HISTOGRAM_POINTER_BLOCK(name, Add(sample), \
199         base::Histogram::FactoryGet(name, min, max, bucket_count, \
200             base::HistogramBase::kUmaTargetedHistogramFlag))
201 
202 #define UMA_HISTOGRAM_MEMORY_KB(name, sample) UMA_HISTOGRAM_CUSTOM_COUNTS( \
203     name, sample, 1000, 500000, 50)
204 
205 #define UMA_HISTOGRAM_MEMORY_MB(name, sample) UMA_HISTOGRAM_CUSTOM_COUNTS( \
206     name, sample, 1, 1000, 50)
207 
208 #define UMA_HISTOGRAM_MEMORY_LARGE_MB(name, sample) \
209     UMA_HISTOGRAM_CUSTOM_COUNTS(name, sample, 1, 64000, 100)
210 
211 #define UMA_HISTOGRAM_PERCENTAGE(name, under_one_hundred) \
212     UMA_HISTOGRAM_ENUMERATION(name, under_one_hundred, 101)
213 
214 #define UMA_HISTOGRAM_BOOLEAN(name, sample) \
215     STATIC_HISTOGRAM_POINTER_BLOCK(name, AddBoolean(sample), \
216         base::BooleanHistogram::FactoryGet(name, \
217             base::HistogramBase::kUmaTargetedHistogramFlag))
218 
219 // The samples should always be strictly less than |boundary_value|.  For more
220 // details, see the comment for the |LOCAL_HISTOGRAM_ENUMERATION| macro, above.
221 #define UMA_HISTOGRAM_ENUMERATION(name, sample, boundary_value) \
222     HISTOGRAM_ENUMERATION_WITH_FLAG(name, sample, boundary_value, \
223         base::HistogramBase::kUmaTargetedHistogramFlag)
224 
225 // Similar to UMA_HISTOGRAM_ENUMERATION, but used for recording stability
226 // histograms.  Use this if recording a histogram that should be part of the
227 // initial stability log.
228 #define UMA_STABILITY_HISTOGRAM_ENUMERATION(name, sample, boundary_value) \
229     HISTOGRAM_ENUMERATION_WITH_FLAG(name, sample, boundary_value, \
230         base::HistogramBase::kUmaStabilityHistogramFlag)
231 
232 #define UMA_HISTOGRAM_CUSTOM_ENUMERATION(name, sample, custom_ranges) \
233     STATIC_HISTOGRAM_POINTER_BLOCK(name, Add(sample), \
234         base::CustomHistogram::FactoryGet(name, custom_ranges, \
235             base::HistogramBase::kUmaTargetedHistogramFlag))
236 
237 // Scoped class which logs its time on this earth as a UMA statistic. This is
238 // recommended for when you want a histogram which measures the time it takes
239 // for a method to execute. This measures up to 10 seconds.
240 #define SCOPED_UMA_HISTOGRAM_TIMER(name) \
241   SCOPED_UMA_HISTOGRAM_TIMER_EXPANDER(name, false, __COUNTER__)
242 
243 // Similar scoped histogram timer, but this uses UMA_HISTOGRAM_LONG_TIMES_100,
244 // which measures up to an hour, and uses 100 buckets. This is more expensive
245 // to store, so only use if this often takes >10 seconds.
246 #define SCOPED_UMA_HISTOGRAM_LONG_TIMER(name) \
247   SCOPED_UMA_HISTOGRAM_TIMER_EXPANDER(name, true, __COUNTER__)
248 
249 // This nested macro is necessary to expand __COUNTER__ to an actual value.
250 #define SCOPED_UMA_HISTOGRAM_TIMER_EXPANDER(name, is_long, key) \
251   SCOPED_UMA_HISTOGRAM_TIMER_UNIQUE(name, is_long, key)
252 
253 #define SCOPED_UMA_HISTOGRAM_TIMER_UNIQUE(name, is_long, key) \
254   class ScopedHistogramTimer##key { \
255    public: \
256     ScopedHistogramTimer##key() : constructed_(base::TimeTicks::Now()) {} \
257     ~ScopedHistogramTimer##key() { \
258       base::TimeDelta elapsed = base::TimeTicks::Now() - constructed_; \
259       if (is_long) { \
260         UMA_HISTOGRAM_LONG_TIMES_100(name, elapsed); \
261       } else { \
262         UMA_HISTOGRAM_TIMES(name, elapsed); \
263       } \
264     } \
265    private: \
266     base::TimeTicks constructed_; \
267   } scoped_histogram_timer_##key
268 
269 #endif  // BASE_METRICS_HISTOGRAM_MACROS_H_
270