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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 // Macros for efficient use of histograms. See documentation in histogram.h.
14 //
15 // UMA_HISTOGRAM_SPARSE_SLOWLY is defined in sparse_histogram.h as it has
16 // different #include dependencies.
17 
18 //------------------------------------------------------------------------------
19 // Histograms are often put in areas where they are called many many times, and
20 // performance is critical.  As a result, they are designed to have a very low
21 // recurring cost of executing (adding additional samples).  Toward that end,
22 // the macros declare a static pointer to the histogram in question, and only
23 // take a "slow path" to construct (or find) the histogram on the first run
24 // through the macro.  We leak the histograms at shutdown time so that we don't
25 // have to validate using the pointers at any time during the running of the
26 // process.
27 
28 // The following code is generally what a thread-safe static pointer
29 // initialization looks like for a histogram (after a macro is expanded).  This
30 // sample is an expansion (with comments) of the code for
31 // LOCAL_HISTOGRAM_CUSTOM_COUNTS().
32 
33 /*
34   do {
35     // The pointer's presence indicates the initialization is complete.
36     // Initialization is idempotent, so it can safely be atomically repeated.
37     static base::subtle::AtomicWord atomic_histogram_pointer = 0;
38 
39     // Acquire_Load() ensures that we acquire visibility to the pointed-to data
40     // in the histogram.
41     base::Histogram* histogram_pointer(reinterpret_cast<base::Histogram*>(
42         base::subtle::Acquire_Load(&atomic_histogram_pointer)));
43 
44     if (!histogram_pointer) {
45       // This is the slow path, which will construct OR find the matching
46       // histogram.  FactoryGet includes locks on a global histogram name map
47       // and is completely thread safe.
48       histogram_pointer = base::Histogram::FactoryGet(
49           name, min, max, bucket_count, base::HistogramBase::kNoFlags);
50 
51       // Use Release_Store to ensure that the histogram data is made available
52       // globally before we make the pointer visible.
53       // Several threads may perform this store, but the same value will be
54       // stored in all cases (for a given named/spec'ed histogram).
55       // We could do this without any barrier, since FactoryGet entered and
56       // exited a lock after construction, but this barrier makes things clear.
57       base::subtle::Release_Store(&atomic_histogram_pointer,
58           reinterpret_cast<base::subtle::AtomicWord>(histogram_pointer));
59     }
60 
61     // Ensure calling contract is upheld, and the name does NOT vary.
62     DCHECK(histogram_pointer->histogram_name() == constant_histogram_name);
63 
64     histogram_pointer->Add(sample);
65   } while (0);
66 */
67 
68 // The above pattern is repeated in several macros.  The only elements that
69 // vary are the invocation of the Add(sample) vs AddTime(sample), and the choice
70 // of which FactoryGet method to use.  The different FactoryGet methods have
71 // various argument lists, so the function with its argument list is provided as
72 // a macro argument here.  The name is only used in a DCHECK, to assure that
73 // callers don't try to vary the name of the histogram (which would tend to be
74 // ignored by the one-time initialization of the histogtram_pointer).
75 
76 // In some cases (integration into 3rd party code), it's useful to seperate the
77 // definition of |atomic_histogram_poiner| from its use. To achieve this we
78 // define HISTOGRAM_POINTER_USE, which uses an |atomic_histogram_pointer|, and
79 // STATIC_HISTOGRAM_POINTER_BLOCK, which defines an |atomic_histogram_pointer|
80 // and forwards to HISTOGRAM_POINTER_USE.
81 #define HISTOGRAM_POINTER_USE(atomic_histogram_pointer,                   \
82                               constant_histogram_name,                    \
83                               histogram_add_method_invocation,            \
84                               histogram_factory_get_invocation)           \
85   do {                                                                    \
86     base::HistogramBase* histogram_pointer(                               \
87         reinterpret_cast<base::HistogramBase*>(                           \
88             base::subtle::Acquire_Load(atomic_histogram_pointer)));       \
89     if (!histogram_pointer) {                                             \
90       histogram_pointer = histogram_factory_get_invocation;               \
91       base::subtle::Release_Store(                                        \
92           atomic_histogram_pointer,                                       \
93           reinterpret_cast<base::subtle::AtomicWord>(histogram_pointer)); \
94     }                                                                     \
95     if (DCHECK_IS_ON())                                                   \
96       histogram_pointer->CheckName(constant_histogram_name);              \
97     histogram_pointer->histogram_add_method_invocation;                   \
98   } while (0)
99 
100 // Defines the static |atomic_histogram_pointer| and forwards to
101 // HISTOGRAM_POINTER_USE.
102 #define STATIC_HISTOGRAM_POINTER_BLOCK(constant_histogram_name,               \
103                                        histogram_add_method_invocation,       \
104                                        histogram_factory_get_invocation)      \
105   do {                                                                        \
106     static base::subtle::AtomicWord atomic_histogram_pointer = 0;             \
107     HISTOGRAM_POINTER_USE(&atomic_histogram_pointer, constant_histogram_name, \
108                           histogram_add_method_invocation,                    \
109                           histogram_factory_get_invocation);                  \
110   } while (0)
111 
112 //------------------------------------------------------------------------------
113 // Provide easy general purpose histogram in a macro, just like stats counters.
114 // Most of these macros use 50 buckets, but check the definition for details.
115 //
116 // All of these macros must be called with |name| as a runtime constant --- it
117 // doesn't have to literally be a constant, but it must be the same string on
118 // all calls from a particular call site. If this rule is violated,
119 // STATIC_HISTOGRAM_POINTER_BLOCK will DCHECK, and if DCHECKS are disabled, the
120 // data will be written to the wrong histogram.
121 
122 #define LOCAL_HISTOGRAM_TIMES(name, sample) LOCAL_HISTOGRAM_CUSTOM_TIMES( \
123     name, sample, base::TimeDelta::FromMilliseconds(1), \
124     base::TimeDelta::FromSeconds(10), 50)
125 
126 // For folks that need real specific times, use this to select a precise range
127 // of times you want plotted, and the number of buckets you want used.
128 #define LOCAL_HISTOGRAM_CUSTOM_TIMES(name, sample, min, max, bucket_count) \
129     STATIC_HISTOGRAM_POINTER_BLOCK(name, AddTime(sample), \
130         base::Histogram::FactoryTimeGet(name, min, max, bucket_count, \
131                                         base::HistogramBase::kNoFlags))
132 
133 #define LOCAL_HISTOGRAM_COUNTS(name, sample) LOCAL_HISTOGRAM_CUSTOM_COUNTS( \
134     name, sample, 1, 1000000, 50)
135 
136 #define LOCAL_HISTOGRAM_COUNTS_100(name, sample) \
137     LOCAL_HISTOGRAM_CUSTOM_COUNTS(name, sample, 1, 100, 50)
138 
139 #define LOCAL_HISTOGRAM_COUNTS_10000(name, sample) \
140     LOCAL_HISTOGRAM_CUSTOM_COUNTS(name, sample, 1, 10000, 50)
141 
142 #define LOCAL_HISTOGRAM_CUSTOM_COUNTS(name, sample, min, max, bucket_count) \
143     STATIC_HISTOGRAM_POINTER_BLOCK(name, Add(sample), \
144         base::Histogram::FactoryGet(name, min, max, bucket_count, \
145                                     base::HistogramBase::kNoFlags))
146 
147 // This is a helper macro used by other macros and shouldn't be used directly.
148 #define HISTOGRAM_ENUMERATION_WITH_FLAG(name, sample, boundary, flag) \
149     STATIC_HISTOGRAM_POINTER_BLOCK(name, Add(sample), \
150         base::LinearHistogram::FactoryGet(name, 1, boundary, boundary + 1, \
151             flag))
152 
153 #define LOCAL_HISTOGRAM_PERCENTAGE(name, under_one_hundred) \
154     LOCAL_HISTOGRAM_ENUMERATION(name, under_one_hundred, 101)
155 
156 #define LOCAL_HISTOGRAM_BOOLEAN(name, sample) \
157     STATIC_HISTOGRAM_POINTER_BLOCK(name, AddBoolean(sample), \
158         base::BooleanHistogram::FactoryGet(name, base::Histogram::kNoFlags))
159 
160 // Support histograming of an enumerated value.  The samples should always be
161 // strictly less than |boundary_value| -- this prevents you from running into
162 // problems down the line if you add additional buckets to the histogram.  Note
163 // also that, despite explicitly setting the minimum bucket value to |1| below,
164 // it is fine for enumerated histograms to be 0-indexed -- this is because
165 // enumerated histograms should never have underflow.
166 #define LOCAL_HISTOGRAM_ENUMERATION(name, sample, boundary_value) \
167     STATIC_HISTOGRAM_POINTER_BLOCK(name, Add(sample), \
168         base::LinearHistogram::FactoryGet(name, 1, boundary_value, \
169             boundary_value + 1, base::HistogramBase::kNoFlags))
170 
171 // Support histograming of an enumerated value. Samples should be one of the
172 // std::vector<int> list provided via |custom_ranges|. See comments above
173 // CustomRanges::FactoryGet about the requirement of |custom_ranges|.
174 // You can use the helper function CustomHistogram::ArrayToCustomRanges to
175 // transform a C-style array of valid sample values to a std::vector<int>.
176 #define LOCAL_HISTOGRAM_CUSTOM_ENUMERATION(name, sample, custom_ranges) \
177     STATIC_HISTOGRAM_POINTER_BLOCK(name, Add(sample), \
178         base::CustomHistogram::FactoryGet(name, custom_ranges, \
179                                           base::HistogramBase::kNoFlags))
180 
181 #define LOCAL_HISTOGRAM_MEMORY_KB(name, sample) LOCAL_HISTOGRAM_CUSTOM_COUNTS( \
182     name, sample, 1000, 500000, 50)
183 
184 //------------------------------------------------------------------------------
185 // The following macros provide typical usage scenarios for callers that wish
186 // to record histogram data, and have the data submitted/uploaded via UMA.
187 // Not all systems support such UMA, but if they do, the following macros
188 // should work with the service.
189 
190 #define UMA_HISTOGRAM_TIMES(name, sample) UMA_HISTOGRAM_CUSTOM_TIMES( \
191     name, sample, base::TimeDelta::FromMilliseconds(1), \
192     base::TimeDelta::FromSeconds(10), 50)
193 
194 #define UMA_HISTOGRAM_MEDIUM_TIMES(name, sample) UMA_HISTOGRAM_CUSTOM_TIMES( \
195     name, sample, base::TimeDelta::FromMilliseconds(10), \
196     base::TimeDelta::FromMinutes(3), 50)
197 
198 // Use this macro when times can routinely be much longer than 10 seconds.
199 #define UMA_HISTOGRAM_LONG_TIMES(name, sample) UMA_HISTOGRAM_CUSTOM_TIMES( \
200     name, sample, base::TimeDelta::FromMilliseconds(1), \
201     base::TimeDelta::FromHours(1), 50)
202 
203 // Use this macro when times can routinely be much longer than 10 seconds and
204 // you want 100 buckets.
205 #define UMA_HISTOGRAM_LONG_TIMES_100(name, sample) UMA_HISTOGRAM_CUSTOM_TIMES( \
206     name, sample, base::TimeDelta::FromMilliseconds(1), \
207     base::TimeDelta::FromHours(1), 100)
208 
209 #define UMA_HISTOGRAM_CUSTOM_TIMES(name, sample, min, max, bucket_count) \
210     STATIC_HISTOGRAM_POINTER_BLOCK(name, AddTime(sample), \
211         base::Histogram::FactoryTimeGet(name, min, max, bucket_count, \
212             base::HistogramBase::kUmaTargetedHistogramFlag))
213 
214 #define UMA_HISTOGRAM_COUNTS(name, sample) UMA_HISTOGRAM_CUSTOM_COUNTS( \
215     name, sample, 1, 1000000, 50)
216 
217 #define UMA_HISTOGRAM_COUNTS_100(name, sample) UMA_HISTOGRAM_CUSTOM_COUNTS( \
218     name, sample, 1, 100, 50)
219 
220 #define UMA_HISTOGRAM_COUNTS_1000(name, sample) UMA_HISTOGRAM_CUSTOM_COUNTS( \
221     name, sample, 1, 1000, 50)
222 
223 #define UMA_HISTOGRAM_COUNTS_10000(name, sample) UMA_HISTOGRAM_CUSTOM_COUNTS( \
224     name, sample, 1, 10000, 50)
225 
226 #define UMA_HISTOGRAM_CUSTOM_COUNTS(name, sample, min, max, bucket_count) \
227     STATIC_HISTOGRAM_POINTER_BLOCK(name, Add(sample), \
228         base::Histogram::FactoryGet(name, min, max, bucket_count, \
229             base::HistogramBase::kUmaTargetedHistogramFlag))
230 
231 #define UMA_HISTOGRAM_MEMORY_KB(name, sample) UMA_HISTOGRAM_CUSTOM_COUNTS( \
232     name, sample, 1000, 500000, 50)
233 
234 #define UMA_HISTOGRAM_MEMORY_MB(name, sample) UMA_HISTOGRAM_CUSTOM_COUNTS( \
235     name, sample, 1, 1000, 50)
236 
237 #define UMA_HISTOGRAM_MEMORY_LARGE_MB(name, sample) \
238     UMA_HISTOGRAM_CUSTOM_COUNTS(name, sample, 1, 64000, 100)
239 
240 #define UMA_HISTOGRAM_PERCENTAGE(name, under_one_hundred) \
241     UMA_HISTOGRAM_ENUMERATION(name, under_one_hundred, 101)
242 
243 #define UMA_HISTOGRAM_BOOLEAN(name, sample) \
244     STATIC_HISTOGRAM_POINTER_BLOCK(name, AddBoolean(sample), \
245         base::BooleanHistogram::FactoryGet(name, \
246             base::HistogramBase::kUmaTargetedHistogramFlag))
247 
248 // The samples should always be strictly less than |boundary_value|.  For more
249 // details, see the comment for the |LOCAL_HISTOGRAM_ENUMERATION| macro, above.
250 #define UMA_HISTOGRAM_ENUMERATION(name, sample, boundary_value) \
251     HISTOGRAM_ENUMERATION_WITH_FLAG(name, sample, boundary_value, \
252         base::HistogramBase::kUmaTargetedHistogramFlag)
253 
254 // Similar to UMA_HISTOGRAM_ENUMERATION, but used for recording stability
255 // histograms.  Use this if recording a histogram that should be part of the
256 // initial stability log.
257 #define UMA_STABILITY_HISTOGRAM_ENUMERATION(name, sample, boundary_value) \
258     HISTOGRAM_ENUMERATION_WITH_FLAG(name, sample, boundary_value, \
259         base::HistogramBase::kUmaStabilityHistogramFlag)
260 
261 #define UMA_HISTOGRAM_CUSTOM_ENUMERATION(name, sample, custom_ranges) \
262     STATIC_HISTOGRAM_POINTER_BLOCK(name, Add(sample), \
263         base::CustomHistogram::FactoryGet(name, custom_ranges, \
264             base::HistogramBase::kUmaTargetedHistogramFlag))
265 
266 // Scoped class which logs its time on this earth as a UMA statistic. This is
267 // recommended for when you want a histogram which measures the time it takes
268 // for a method to execute. This measures up to 10 seconds.
269 #define SCOPED_UMA_HISTOGRAM_TIMER(name) \
270   SCOPED_UMA_HISTOGRAM_TIMER_EXPANDER(name, false, __COUNTER__)
271 
272 // Similar scoped histogram timer, but this uses UMA_HISTOGRAM_LONG_TIMES_100,
273 // which measures up to an hour, and uses 100 buckets. This is more expensive
274 // to store, so only use if this often takes >10 seconds.
275 #define SCOPED_UMA_HISTOGRAM_LONG_TIMER(name) \
276   SCOPED_UMA_HISTOGRAM_TIMER_EXPANDER(name, true, __COUNTER__)
277 
278 // This nested macro is necessary to expand __COUNTER__ to an actual value.
279 #define SCOPED_UMA_HISTOGRAM_TIMER_EXPANDER(name, is_long, key) \
280   SCOPED_UMA_HISTOGRAM_TIMER_UNIQUE(name, is_long, key)
281 
282 #define SCOPED_UMA_HISTOGRAM_TIMER_UNIQUE(name, is_long, key) \
283   class ScopedHistogramTimer##key { \
284    public: \
285     ScopedHistogramTimer##key() : constructed_(base::TimeTicks::Now()) {} \
286     ~ScopedHistogramTimer##key() { \
287       base::TimeDelta elapsed = base::TimeTicks::Now() - constructed_; \
288       if (is_long) { \
289         UMA_HISTOGRAM_LONG_TIMES_100(name, elapsed); \
290       } else { \
291         UMA_HISTOGRAM_TIMES(name, elapsed); \
292       } \
293     } \
294    private: \
295     base::TimeTicks constructed_; \
296   } scoped_histogram_timer_##key
297 
298 #endif  // BASE_METRICS_HISTOGRAM_MACROS_H_
299