third_party/tcmalloc/chromium/src/gperftools/profiler.h

   1 /* Copyright (c) 2005, Google Inc.
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   4  * Redistribution and use in source and binary forms, with or without
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  16  * this software without specific prior written permission.
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  18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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  20  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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  24  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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  28  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  29  *
  30  * ---
  31  * Author: Sanjay Ghemawat
  32  *
  33  * Module for CPU profiling based on periodic pc-sampling.
  34  *
  35  * For full(er) information, see doc/cpuprofile.html
  36  *
  37  * This module is linked into your program with
  38  * no slowdown caused by this unless you activate the profiler
  39  * using one of the following methods:
  40  *
  41  *    1. Before starting the program, set the environment variable
  42  *       "PROFILE" to be the name of the file to which the profile
  43  *       data should be written.
  44  *
  45  *    2. Programmatically, start and stop the profiler using the
  46  *       routines "ProfilerStart(filename)" and "ProfilerStop()".
  47  *
  48  *
  49  * (Note: if using linux 2.4 or earlier, only the main thread may be
  50  * profiled.)
  51  *
  52  * Use pprof to view the resulting profile output.
  53  *    % pprof <path_to_executable> <profile_file_name>
  54  *    % pprof --gv  <path_to_executable> <profile_file_name>
  55  *
  56  * These functions are thread-safe.
  57  */
  58
  59 #ifndef BASE_PROFILER_H_
  60 #define BASE_PROFILER_H_
  61
  62 #include <time.h>       /* For time_t */
  63
  64 /* Annoying stuff for windows; makes sure clients can import these functions */
  65 #ifndef PERFTOOLS_DLL_DECL
  66 # ifdef _WIN32
  67 #   define PERFTOOLS_DLL_DECL  __declspec(dllimport)
  68 # else
  69 #   define PERFTOOLS_DLL_DECL
  70 # endif
  71 #endif
  72
  73 /* All this code should be usable from within C apps. */
  74 #ifdef __cplusplus
  75 extern "C" {
  76 #endif
  77
  78 /* Profiler options, for use with ProfilerStartWithOptions.  To use:
  79  *
  80  *   struct ProfilerOptions options;
  81  *   memset(&options, 0, sizeof options);
  82  *
  83  * then fill in fields as needed.
  84  *
  85  * This structure is intended to be usable from C code, so no constructor
  86  * is provided to initialize it.  (Use memset as described above).
  87  */
  88 struct ProfilerOptions {
  89   /* Filter function and argument.
  90    *
  91    * If filter_in_thread is not NULL, when a profiling tick is delivered
  92    * the profiler will call:
  93    *
  94    *   (*filter_in_thread)(filter_in_thread_arg)
  95    *
  96    * If it returns nonzero, the sample will be included in the profile.
  97    * Note that filter_in_thread runs in a signal handler, so must be
  98    * async-signal-safe.
  99    *
 100    * A typical use would be to set up filter results for each thread
 101    * in the system before starting the profiler, then to make
 102    * filter_in_thread be a very simple function which retrieves those
 103    * results in an async-signal-safe way.  Retrieval could be done
 104    * using thread-specific data, or using a shared data structure that
 105    * supports async-signal-safe lookups.
 106    */
 107   int (*filter_in_thread)(void *arg);
 108   void *filter_in_thread_arg;
 109 };
 110
 111 /* Start profiling and write profile info into fname.
 112  *
 113  * This is equivalent to calling ProfilerStartWithOptions(fname, NULL).
 114  */
 115 PERFTOOLS_DLL_DECL int ProfilerStart(const char* fname);
 116
 117 /* Start profiling and write profile into fname.
 118  *
 119  * The profiler is configured using the options given by 'options'.
 120  * Options which are not specified are given default values.
 121  *
 122  * 'options' may be NULL, in which case all are given default values.
 123  *
 124  * Returns nonzero if profiling was started sucessfully, or zero else.
 125  */
 126 PERFTOOLS_DLL_DECL int ProfilerStartWithOptions(
 127     const char *fname, const struct ProfilerOptions *options);
 128
 129 /* Stop profiling. Can be started again with ProfilerStart(), but
 130  * the currently accumulated profiling data will be cleared.
 131  */
 132 PERFTOOLS_DLL_DECL void ProfilerStop();
 133
 134 /* Flush any currently buffered profiling state to the profile file.
 135  * Has no effect if the profiler has not been started.
 136  */
 137 PERFTOOLS_DLL_DECL void ProfilerFlush();
 138
 139
 140 /* DEPRECATED: these functions were used to enable/disable profiling
 141  * in the current thread, but no longer do anything.
 142  */
 143 PERFTOOLS_DLL_DECL void ProfilerEnable();
 144 PERFTOOLS_DLL_DECL void ProfilerDisable();
 145
 146 /* Returns nonzero if profile is currently enabled, zero if it's not. */
 147 PERFTOOLS_DLL_DECL int ProfilingIsEnabledForAllThreads();
 148
 149 /* Routine for registering new threads with the profiler.
 150  */
 151 PERFTOOLS_DLL_DECL void ProfilerRegisterThread();
 152
 153 /* Stores state about profiler's current status into "*state". */
 154 struct ProfilerState {
 155   int    enabled;             /* Is profiling currently enabled? */
 156   time_t start_time;          /* If enabled, when was profiling started? */
 157   char   profile_name[1024];  /* Name of profile file being written, or '\0' */
 158   int    samples_gathered;    /* Number of samples gathered so far (or 0) */
 159 };
 160 PERFTOOLS_DLL_DECL void ProfilerGetCurrentState(struct ProfilerState* state);
 161
 162 #ifdef __cplusplus
 163 }  // extern "C"
 164 #endif
 165
 166 #endif  /* BASE_PROFILER_H_ */