BFS vs. mainline scheduler benchmarks and measurements

Posted Sep 7, 2009 13:11 UTC (Mon) by mingo (subscriber, #31122)
In reply to: BFS vs. mainline scheduler benchmarks and measurements by ikm
Parent article: BFS vs. mainline scheduler benchmarks and measurements

But how are you going to measure things like:

* mplayer using OpenGL renderer doesn't drop frames anymore when dragging and dropping the video window around in an OpenGL composited desktop

* Composite desktop effects like zoom and fade out don't stall for sub-second periods of time while there's CPU load in the background

* LMMS (a tool utilizing real-time sound synthesis) does not produce "pops", "crackles" and drops in the sound during real-time playback due to buffer under-runs

* Games like Doom 3 and such don't "freeze" periodically for small amounts of time (again for sub-second amounts) when something in the background grabs CPU time

This is a list of routine interactivity problems that we track down and address. In the past few years we've got extensive infrastructure built up in the mainline kernel that allows their measurement and allows us to eliminate them.

A good place to start would be to try the latency tracing suggestions from Frederic Weisbecker on lkml:

Such properties of the desktop are measured routinely (sometimes easily - sometimes it needs quite a bit of work) - so please report them and help out tracking them down.

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BFS vs. mainline scheduler benchmarks and measurements

Posted Sep 7, 2009 14:02 UTC (Mon) by ikm (subscriber, #493) [Link] (1 responses)

Yay, that's a start. I hope this can go somewhere eventually. Clearly it's the interactivity issues Con has always been after, not the bulk workloads. With a way to measure and quantify those issues and scenarios, something might get going somewhere.

BFS vs. mainline scheduler benchmarks and measurements

Posted Sep 7, 2009 21:53 UTC (Mon) by mingo (subscriber, #31122) [Link]

You might want to try latencytop. We added the instrumentation for that after the CFS merge - to make it easier to prove/report scheduler (and other) latencies.