Unreal's GameThread is missing in profile.json but present in .etl file

[jsjtxietian]

Hi Thanks for the great work, I really love the idea of converting .etl file to gecko, the firefox profiler is great.

When I profile my unreal game, I noticed that a thread named "GameThread" is missing in the output profile.json.gz, but I can see it in the .elf file, and I tried with vtune too it can also display the Gamethread. Because the gamethread is the most important one, and it's the main thread, so it's a little annoying.

Update: I read the code and find that it will overwrite the main thread's name to process's name when serializing to gecko json, so I did not find the "GameThread" in the json output, can this be improved a bit to avoid misunderstanding ? If so I'm happy to help.

[mstange]

Oh, does it actually overwrite the thread name? That is indeed misleading.
The UI displays the main thread in a "track" that's labelled with the process name. But you should be able to get the original thread name from the tooltip of that process label. If we don't show the original thread name in the tooltip, that's something we should fix.

[jsjtxietian]

But you should be able to get the original thread name from the tooltip of that process label.

Unfortunately no. See:

Thread name should be "GameThread".

Related code is here, the thread name is over written if it's the main thread:

samply/fxprof-processed-profile/src/thread.rs

Lines 286 to 290 in a603f90

	let thread_name: Cow<str> = match (self.is_main, &self.name) {
	(true, _) => process_name.into(),
	(false, Some(name)) => name.into(),
	(false, None) => format!("Thread <{}>", self.tid).into(),
	};

I guess the impl here makes sense for most of the app where the main thread does not have a name or do the heavy work alone, but for games it's not that fit as we often want to check like "GameThread" "RenderThread" instead of just the process's name.