jak-project/common/global_profiler
Tyler Wilding 60db0e5ef9
deps: update fmt to latest version (#3403)
This updates `fmt` to the latest version and moves to just being a copy
of their repo to make updating easier (no editing their cmake / figuring
out which files to minimally include).

The motivation for this is now that we switched to C++ 20, there were a
ton of deprecated function usages that is going away in future compiler
versions. This gets rid of all those warnings.
2024-03-05 22:11:52 -05:00
..
GlobalProfiler.cpp deps: update fmt to latest version (#3403) 2024-03-05 22:11:52 -05:00
GlobalProfiler.h tracing: add some more startup related events and a new --profile-until-event flag (#3385) 2024-02-23 14:44:17 -05:00
readme.md Add timeline style profiler (#1312) 2022-04-17 21:12:24 -04:00

Event Profiler

The event profiler is a tool to analyze timing of multiple frames. Unlike sampling-based profilers, this profile captures an exact timeline of what happens of what happens when.

Capturing a profile

In the OpenGOAL window, click "Profiler" and check "Record" to start recording. The buffer has a fixed maximum size and it will automatically overwrite old data once it is full.

When something interesting happens, click the "dump to file" button to save the buffer (currently a few seconds) to prof.json in jak-project.

The idea is that you can leave this running as you play, and then when the game stutters or does something interesting, you can click the dump button and get the result.

Viewing a profile

Open Google Chrome and go to chrome://tracing. Then click load and open the json file. Or, just drag and drop the file into chrome.

Press 1 for a box drawing tool. This lets you select a region of the flame chart and get a list of events inside the box.

Press 2 for panning.

Press 3 for zooming.

Adding an event

The GOAL kernel automatically adds events for each process. If you want to add another event, you can use (with-profiler "name-of-event" <body>). Do not call suspend or do a return inside of this. If you need more control over stopping/starting, there are functions in gcommon.gc to explicitly start/stop events. But you must match them up correctly yourself!

In C++, the graphics profiler automatically adds a profiler nodes as events. To add an event, you can use

auto p = scoped_prof("name-of-event");

The event is active from this call until the destruction of p.

Multiple threads

The event profiler currently works on both the graphics and EE threads. Adding the events can safely be done from any thread, but enable/disable/dump should be done from a single thread at a time.

Each thread should periodically insert a ROOT instant event when there are no active range events. This is required to make the retroactive dump feature work properly as the event buffer does not capture the tree structure fully, and it must be able to find a point in time when no events are active.