pjs/tools/profiler/sampler.h

80 строки
3.2 KiB
C

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
/* *************** SPS Sampler Information ****************
*
* SPS is an always on profiler that takes fast and low overheads samples
* of the program execution using only userspace functionity for portability.
* The goal of this module is to provide performance data in a generic
* cross platform way without requiring custom tools or kernel support.
*
* Non goals: Support features that are platform specific or replace
* platform specific profilers.
*
* Samples are collected to form a timeline with optional timeline event (markers)
* used for filtering.
*
* SPS collects samples in a platform independant way by using a speudo stack abstraction
* of the real program stack by using 'sample stack frames'. When a sample is collected
* all active sample stack frames and the program counter are recorded.
*/
/* *************** SPS Sampler File Format ****************
*
* Simple new line seperated tag format:
* S -> BOF tags EOF
* tags -> tag tags
* tag -> CHAR - STRING
*
* Tags:
* 's' - Sample tag followed by the first stack frame followed by 0 or more 'c' tags.
* 'c' - Continue Sample tag gives remaining tag element. If a 'c' tag is seen without
* a preceding 's' tag it should be ignored. This is to support the behavior
* of circular buffers.
* If the 'stackwalk' feature is enabled this tag will have the format
* 'l-<library name>@<hex address>' and will expect an external tool to translate
* the tag into something readable through a symbolication processing step.
* 'm' - Timeline marker. Zero or more may appear before a 's' tag.
* 'l' - Information about the program counter library and address. Post processing
* can include function and source line. If built with leaf data enabled
* this tag will describe the last 'c' tag.
* 'r' - Responsiveness tag following an 's' tag. Gives an indication on how well the
* application is responding to the event loop. Lower is better.
*
* NOTE: File format is planned to be extended to include a dictionary to reduce size.
*/
#ifndef SAMPLER_H
#define SAMPLER_H
// Redefine the macros for platforms where SPS is supported.
#ifdef MOZ_ENABLE_PROFILER_SPS
#include "sps_sampler.h"
#else
// Initialize the sampler. Any other calls will be silently discarded
// before the sampler has been initialized (i.e. early start-up code)
#define SAMPLER_INIT()
#define SAMPLER_DEINIT()
#define SAMPLER_START(entries, interval, features, featureCount)
#define SAMPLER_STOP()
#define SAMPLER_IS_ACTIVE() false
#define SAMPLER_SAVE()
// Returned string must be free'ed
#define SAMPLER_GET_PROFILE() NULL
#define SAMPLER_GET_PROFILE_DATA(ctx) NULL
#define SAMPLER_RESPONSIVENESS(time) NULL
#define SAMPLER_GET_RESPONSIVENESS() NULL
#define SAMPLER_GET_FEATURES() NULL
#define SAMPLE_LABEL(name_space, info)
#define SAMPLE_LABEL_FN(name_space, info)
#define SAMPLE_MARKER(info)
#endif
#endif // ifndef SAMPLER_H