Support higher CPU profiler sampling rate on posix systems

src/profile-generator.h

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 315 matching lines @@
   Semaphore* current_profiles_semaphore_;
 
   DISALLOW_COPY_AND_ASSIGN(CpuProfilesCollection);
 };
 
 
 class SampleRateCalculator {
  public:
   SampleRateCalculator()
       : result_(Logger::kSamplingIntervalMs * kResultScale),
-        ticks_per_ms_(Logger::kSamplingIntervalMs),
+        ticks_per_ms_(1.0 / Logger::kSamplingIntervalMs),
         measurements_count_(0),
         wall_time_query_countdown_(1) {
   }
 
   double ticks_per_ms() {
     return result_ / static_cast<double>(kResultScale);
   }
   void Tick();
   void UpdateMeasurements(double current_time);
 
@@ skipping 50 matching lines @@
   CodeEntry* unresolved_entry_;
   SampleRateCalculator sample_rate_calc_;
 
   DISALLOW_COPY_AND_ASSIGN(ProfileGenerator);
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_PROFILE_GENERATOR_H_