gecko-dev/xpcom/base/VisualEventTracer.h

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/* 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/. */
/* Visual event tracer, creates a log of events on each thread for visualization */
/**
* The event tracer code is by default disabled in both build and run time.
*
* To enable this code at build time, add --enable-visual-profiling to your
* configure options.
*
* To enable this code at run time, export MOZ_PROFILING_FILE env var with
* a path to the file to write the log to. This is all you need to produce
* the log of all events instrumentation in the mozilla code.
* Check MOZ_EVENT_TRACER_* macros bellow to add your own.
*
* To let the event tracer log only some events to save disk space, export
* MOZ_PROFILING_EVENTS with comma separated list of event names you want
* to record in the log.
*/
#include "nscore.h"
#include "mozilla/GuardObjects.h"
#ifdef MOZ_VISUAL_EVENT_TRACER
// Bind an object instance, usually |this|, to a name, usually URL or
// host name, the instance deals with for its lifetime. The name string
// is duplicated.
// IMPORTANT: it is up to the caller to pass the correct static_cast
// of the |instance| pointer to all these macros ; otherwise the linking
// of events and objects will not work!
// The name will show in details of the events on the timeline and also
// will allow events filtering by host names, URLs etc.
#define MOZ_EVENT_TRACER_NAME_OBJECT(instance, name) \
mozilla::eventtracer::Mark(mozilla::eventtracer::eName, instance, name)
// The same as MOZ_EVENT_TRACER_NAME_OBJECT, just simplifies building
// names when it consists of two parts
#define MOZ_EVENT_TRACER_COMPOUND_NAME(instance, name, name2) \
mozilla::eventtracer::Mark(mozilla::eventtracer::eName, instance, name, name2)
// Call the followings with the same |instance| reference as you have
// previously called MOZ_EVENT_TRACER_NAME_OBJECT.
// Let |name| be the name of the event happening, like "resolving",
// "connecting", "loading" etc.
// This will crate a single-point-in-time event marked with an arrow
// on the timeline, this is a way to indicate an event without a duration.
#define MOZ_EVENT_TRACER_MARK(instance, name) \
mozilla::eventtracer::Mark(mozilla::eventtracer::eShot, instance, name)
// Following macros are used to log events with duration.
// There always has to be complete WAIT,EXEC,DONE or EXEC,DONE
// uninterrupted and non-interferring tuple(s) for an event to be correctly
// shown on the timeline. Each can be called on any thread, the event tape is
// finally displayed on the thread where it has been EXECuted.
// Example of 3 phases usage for "HTTP request channel":
// WAIT: we've just created the channel and called AsyncOpen on it
// EXEC: we've just got first call to OnDataAvailable, so we are actually
// receiving the content after some time like connection establising,
// opening a cache entry, sending the GET request...
// DONE: we've just got OnStopRequest call that indicates the content
// has been completely delivered and the request is now finished
// Indicate an event pending start, on the timeline this will
// start the event's interval tape with a pale color, the time will
// show in details. Usually used when an event is being posted or
// we wait for a lock acquisition.
// WAITING is not mandatory, some events don't have a pending phase.
#define MOZ_EVENT_TRACER_WAIT(instance, name) \
mozilla::eventtracer::Mark(mozilla::eventtracer::eWait, instance, name)
// Indicate start of an event actual execution, on the timeline this will
// change the event's tape to a deeper color, the time will show in details.
#define MOZ_EVENT_TRACER_EXEC(instance, name) \
mozilla::eventtracer::Mark(mozilla::eventtracer::eExec, instance, name)
// Indicate the end of an event execution (the event has been done),
// on the timeline this will end the event's tape and show the time in
// event details.
// NOTE: when the event duration is extremely short, like 1ms, it will convert
// to an event w/o a duration - the same as MOZ_EVENT_TRACER_MARK would be used.
#define MOZ_EVENT_TRACER_DONE(instance, name) \
mozilla::eventtracer::Mark(mozilla::eventtracer::eDone, instance, name)
// The same meaning as the above macros, just for concurent events.
// Concurent event means it can happen for the same instance on more
// then just a single thread, e.g. a service method call, a global lock
// acquisition, enter and release.
#define MOZ_EVENT_TRACER_WAIT_THREADSAFE(instance, name) \
mozilla::eventtracer::Mark(mozilla::eventtracer::eWait | mozilla::eventtracer::eThreadConcurrent, instance, name)
#define MOZ_EVENT_TRACER_EXEC_THREADSAFE(instance, name) \
mozilla::eventtracer::Mark(mozilla::eventtracer::eExec | mozilla::eventtracer::eThreadConcurrent, instance, name)
#define MOZ_EVENT_TRACER_DONE_THREASAFE(instance, name) \
mozilla::eventtracer::Mark(mozilla::eventtracer::eDone | mozilla::eventtracer::eThreadConcurrent, instance, name)
#else
// MOZ_VISUAL_EVENT_TRACER disabled
#define MOZ_EVENT_TRACER_NAME_OBJECT(instance, name) (void)0
#define MOZ_EVENT_TRACER_COMPOUND_NAME(instance, name, name2) (void)0
#define MOZ_EVENT_TRACER_MARK(instance, name) (void)0
#define MOZ_EVENT_TRACER_WAIT(instance, name) (void)0
#define MOZ_EVENT_TRACER_EXEC(instance, name) (void)0
#define MOZ_EVENT_TRACER_DONE(instance, name) (void)0
#define MOZ_EVENT_TRACER_WAIT_THREADSAFE(instance, name) (void)0
#define MOZ_EVENT_TRACER_EXEC_THREADSAFE(instance, name) (void)0
#define MOZ_EVENT_TRACER_DONE_THREASAFE(instance, name) (void)0
#endif
namespace mozilla { namespace eventtracer {
// Initialize the event tracer engine, called automatically on XPCOM startup.
void Init();
// Shuts the event tracer engine down and closes the log file, called
// automatically during XPCOM shutdown.
void Shutdown();
enum MarkType {
eNone, // No operation, ignored
eName, // This is used to bind an object instance with a name
eShot, // An event with no duration
eWait, // Start of waiting for execution (lock acquire, post...)
eExec, // Start of the execution it self
eDone, // End of the execution
eLast, // Sentinel
// Flags
// The same object can execute the same event on several threads concurently
eThreadConcurrent = 0x10000
};
// Records an event on the calling thread.
// @param aType
// One of MarkType fields, can be bitwise or'ed with the flags.
// @param aItem
// Reference to the object we want to bind a name to or the event is
// happening on. Can be actually anything, but valid poitners should
// be used.
// @param aText
// Text of the name (for eName) or event's name for others. The string
// is duplicated.
// @param aText2
// Optional second part of the instnace name, or event name.
// Event filtering does apply only to the first part (aText).
void Mark(uint32_t aType, void * aItem,
const char * aText, const char * aText2 = 0);
// Helper guard object. Use to mark an event in the constructor and a different
// event in the destructor.
//
// Example:
// int class::func()
// {
// AutoEventTracer tracer(this, eventtracer::eExec, eventtracer::eDone, "func");
//
// do_something_taking_a_long_time();
// }
class NS_STACK_CLASS AutoEventTracer
{
public:
AutoEventTracer(void * aInstance,
uint32_t aTypeOn, // MarkType marked in constructor
uint32_t aTypeOff, // MarkType marked in destructor
const char * aName,
const char * aName2 = 0
MOZ_GUARD_OBJECT_NOTIFIER_PARAM)
: mInstance(aInstance)
, mName(aName)
, mName2(aName2)
, mTypeOn(aTypeOn)
, mTypeOff(aTypeOff)
{
MOZ_GUARD_OBJECT_NOTIFIER_INIT;
::mozilla::eventtracer::Mark(mTypeOn, mInstance, mName, mName2);
}
~AutoEventTracer()
{
::mozilla::eventtracer::Mark(mTypeOff, mInstance, mName, mName2);
}
private:
void * mInstance;
const char * mName;
const char * mName2;
uint32_t mTypeOn;
uint32_t mTypeOff;
MOZ_DECL_USE_GUARD_OBJECT_NOTIFIER
};
} // eventtracer
} // mozilla