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      1 /*
      2  * libjingle
      3  * Copyright 2013, Google Inc.
      4  *
      5  * Redistribution and use in source and binary forms, with or without
      6  * modification, are permitted provided that the following conditions are met:
      7  *
      8  *  1. Redistributions of source code must retain the above copyright notice,
      9  *     this list of conditions and the following disclaimer.
     10  *  2. Redistributions in binary form must reproduce the above copyright notice,
     11  *     this list of conditions and the following disclaimer in the documentation
     12  *     and/or other materials provided with the distribution.
     13  *  3. The name of the author may not be used to endorse or promote products
     14  *     derived from this software without specific prior written permission.
     15  *
     16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
     17  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
     18  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
     19  * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     20  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
     21  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
     22  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
     23  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
     24  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
     25  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     26  */
     27 
     28 #include "talk/base/profiler.h"
     29 
     30 #include <math.h>
     31 
     32 #include "talk/base/timeutils.h"
     33 
     34 namespace {
     35 
     36 // When written to an ostream, FormattedTime chooses an appropriate scale and
     37 // suffix for a time value given in seconds.
     38 class FormattedTime {
     39  public:
     40   explicit FormattedTime(double t) : time_(t) {}
     41   double time() const { return time_; }
     42  private:
     43   double time_;
     44 };
     45 
     46 std::ostream& operator<<(std::ostream& stream, const FormattedTime& time) {
     47   if (time.time() < 1.0) {
     48     stream << (time.time() * 1000.0) << "ms";
     49   } else {
     50     stream << time.time() << 's';
     51   }
     52   return stream;
     53 }
     54 
     55 }  // namespace
     56 
     57 namespace talk_base {
     58 
     59 ProfilerEvent::ProfilerEvent()
     60     : total_time_(0.0),
     61       mean_(0.0),
     62       sum_of_squared_differences_(0.0),
     63       start_count_(0),
     64       event_count_(0) {
     65 }
     66 
     67 void ProfilerEvent::Start() {
     68   if (start_count_ == 0) {
     69     current_start_time_ = TimeNanos();
     70   }
     71   ++start_count_;
     72 }
     73 
     74 void ProfilerEvent::Stop() {
     75   uint64 stop_time = TimeNanos();
     76   --start_count_;
     77   ASSERT(start_count_ >= 0);
     78   if (start_count_ == 0) {
     79     double elapsed = static_cast<double>(stop_time - current_start_time_) /
     80         kNumNanosecsPerSec;
     81     total_time_ += elapsed;
     82     if (event_count_ == 0) {
     83       minimum_ = maximum_ = elapsed;
     84     } else {
     85       minimum_ = _min(minimum_, elapsed);
     86       maximum_ = _max(maximum_, elapsed);
     87     }
     88     // Online variance and mean algorithm: http://en.wikipedia.org/wiki/
     89     // Algorithms_for_calculating_variance#Online_algorithm
     90     ++event_count_;
     91     double delta = elapsed - mean_;
     92     mean_ = mean_ + delta / event_count_;
     93     sum_of_squared_differences_ += delta * (elapsed - mean_);
     94   }
     95 }
     96 
     97 double ProfilerEvent::standard_deviation() const {
     98     if (event_count_ <= 1) return 0.0;
     99     return sqrt(sum_of_squared_differences_ / (event_count_ - 1.0));
    100 }
    101 
    102 Profiler* Profiler::Instance() {
    103   LIBJINGLE_DEFINE_STATIC_LOCAL(Profiler, instance, ());
    104   return &instance;
    105 }
    106 
    107 void Profiler::StartEvent(const std::string& event_name) {
    108   events_[event_name].Start();
    109 }
    110 
    111 void Profiler::StopEvent(const std::string& event_name) {
    112   events_[event_name].Stop();
    113 }
    114 
    115 void Profiler::ReportToLog(const char* file, int line,
    116                            LoggingSeverity severity_to_use,
    117                            const std::string& event_prefix) {
    118   if (!LogMessage::Loggable(severity_to_use)) {
    119     return;
    120   }
    121   { // Output first line.
    122     LogMessage msg(file, line, severity_to_use);
    123     msg.stream() << "=== Profile report ";
    124     if (event_prefix.empty()) {
    125       msg.stream() << "(prefix: '" << event_prefix << "') ";
    126     }
    127     msg.stream() << "===";
    128   }
    129   typedef std::map<std::string, ProfilerEvent>::const_iterator iterator;
    130   for (iterator it = events_.begin(); it != events_.end(); ++it) {
    131     if (event_prefix.empty() || it->first.find(event_prefix) == 0) {
    132       LogMessage(file, line, severity_to_use).stream()
    133           << it->first << " count=" << it->second.event_count()
    134           << " total=" << FormattedTime(it->second.total_time())
    135           << " mean=" << FormattedTime(it->second.mean())
    136           << " min=" << FormattedTime(it->second.minimum())
    137           << " max=" << FormattedTime(it->second.maximum())
    138           << " sd=" << it->second.standard_deviation();
    139     }
    140   }
    141   LogMessage(file, line, severity_to_use).stream()
    142       << "=== End profile report ===";
    143 }
    144 
    145 void Profiler::ReportAllToLog(const char* file, int line,
    146                            LoggingSeverity severity_to_use) {
    147   ReportToLog(file, line, severity_to_use, "");
    148 }
    149 
    150 const ProfilerEvent* Profiler::GetEvent(const std::string& event_name) const {
    151   std::map<std::string, ProfilerEvent>::const_iterator it =
    152       events_.find(event_name);
    153   return (it == events_.end()) ? NULL : &it->second;
    154 }
    155 
    156 bool Profiler::Clear() {
    157   bool result = true;
    158   // Clear all events that aren't started.
    159   std::map<std::string, ProfilerEvent>::iterator it = events_.begin();
    160   while (it != events_.end()) {
    161     if (it->second.is_started()) {
    162       ++it;  // Can't clear started events.
    163       result = false;
    164     } else {
    165       events_.erase(it++);
    166     }
    167   }
    168   return result;
    169 }
    170 
    171 }  // namespace talk_base
    172