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Diffstat (limited to 'third_party/tcmalloc/vendor/src/profiledata.h')
| -rw-r--r-- | third_party/tcmalloc/vendor/src/profiledata.h | 183 |
1 files changed, 183 insertions, 0 deletions
diff --git a/third_party/tcmalloc/vendor/src/profiledata.h b/third_party/tcmalloc/vendor/src/profiledata.h new file mode 100644 index 0000000..da7ea9e --- /dev/null +++ b/third_party/tcmalloc/vendor/src/profiledata.h @@ -0,0 +1,183 @@ +// Copyright (c) 2007, Google Inc. +// 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 with the +// distribution. +// * Neither the name of Google Inc. nor the names of its +// contributors may be used to endorse or promote products derived from +// this software without specific prior written permission. +// +// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR +// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT +// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT +// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, +// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY +// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE +// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. +// +// --- +// Author: Sanjay Ghemawat +// Chris Demetriou (refactoring) +// +// Collect profiling data. +// +// The profile data file format is documented in +// doc/cpuprofile-fileformat.html + + +#ifndef BASE_PROFILEDATA_H_ +#define BASE_PROFILEDATA_H_ + +#include <config.h> +#include <time.h> // for time_t +#include <stdint.h> +#include "base/basictypes.h" + +// A class that accumulates profile samples and writes them to a file. +// +// Each sample contains a stack trace and a count. Memory usage is +// reduced by combining profile samples that have the same stack trace +// by adding up the associated counts. +// +// Profile data is accumulated in a bounded amount of memory, and will +// flushed to a file as necessary to stay within the memory limit. +// +// Use of this class assumes external synchronization. The exact +// requirements of that synchronization are that: +// +// - 'Add' may be called from asynchronous signals, but is not +// re-entrant. +// +// - None of 'Start', 'Stop', 'Reset', 'Flush', and 'Add' may be +// called at the same time. +// +// - 'Start', 'Stop', or 'Reset' should not be called while 'Enabled' +// or 'GetCurrent' are running, and vice versa. +// +// A profiler which uses asyncronous signals to add samples will +// typically use two locks to protect this data structure: +// +// - A SpinLock which is held over all calls except for the 'Add' +// call made from the signal handler. +// +// - A SpinLock which is held over calls to 'Start', 'Stop', 'Reset', +// 'Flush', and 'Add'. (This SpinLock should be acquired after +// the first SpinLock in all cases where both are needed.) +class ProfileData { + public: + struct State { + bool enabled; // Is profiling currently enabled? + time_t start_time; // If enabled, when was profiling started? + char profile_name[1024]; // Name of file being written, or '\0' + int samples_gathered; // Number of samples gathered to far (or 0) + }; + + class Options { + public: + Options(); + + // Get and set the sample frequency. + int frequency() const { + return frequency_; + } + void set_frequency(int frequency) { + frequency_ = frequency; + } + + private: + int frequency_; // Sample frequency. + }; + + static const int kMaxStackDepth = 64; // Max stack depth stored in profile + + ProfileData(); + ~ProfileData(); + + // If data collection is not already enabled start to collect data + // into fname. Parameters related to this profiling run are specified + // by 'options'. + // + // Returns true if data collection could be started, otherwise (if an + // error occurred or if data collection was already enabled) returns + // false. + bool Start(const char *fname, const Options& options); + + // If data collection is enabled, stop data collection and write the + // data to disk. + void Stop(); + + // Stop data collection without writing anything else to disk, and + // discard any collected data. + void Reset(); + + // If data collection is enabled, record a sample with 'depth' + // entries from 'stack'. (depth must be > 0.) At most + // kMaxStackDepth stack entries will be recorded, starting with + // stack[0]. + // + // This function is safe to call from asynchronous signals (but is + // not re-entrant). + void Add(int depth, const void* const* stack); + + // If data collection is enabled, write the data to disk (and leave + // the collector enabled). + void FlushTable(); + + // Is data collection currently enabled? + bool enabled() const { return out_ >= 0; } + + // Get the current state of the data collector. + void GetCurrentState(State* state) const; + + private: + static const int kAssociativity = 4; // For hashtable + static const int kBuckets = 1 << 10; // For hashtable + static const int kBufferLength = 1 << 18; // For eviction buffer + + // Type of slots: each slot can be either a count, or a PC value + typedef uintptr_t Slot; + + // Hash-table/eviction-buffer entry (a.k.a. a sample) + struct Entry { + Slot count; // Number of hits + Slot depth; // Stack depth + Slot stack[kMaxStackDepth]; // Stack contents + }; + + // Hash table bucket + struct Bucket { + Entry entry[kAssociativity]; + }; + + Bucket* hash_; // hash table + Slot* evict_; // evicted entries + int num_evicted_; // how many evicted entries? + int out_; // fd for output file. + int count_; // How many samples recorded + int evictions_; // How many evictions + size_t total_bytes_; // How much output + char* fname_; // Profile file name + time_t start_time_; // Start time, or 0 + + // Move 'entry' to the eviction buffer. + void Evict(const Entry& entry); + + // Write contents of eviction buffer to disk. + void FlushEvicted(); + + DISALLOW_EVIL_CONSTRUCTORS(ProfileData); +}; + +#endif // BASE_PROFILEDATA_H_ |