Mixxx

soundmanager pushBuffer is inefficient

Bug #682527 reported by Owen Williams on 2010-11-29

This bug affects 1 person

	Status	Importance	Assigned to	Milestone
Mixxx	Fix Released	High	Owen Williams
1.8	Fix Released	High	Owen Williams	Mixxx 1.8.2
1.9	Fix Released	High	Owen Williams	Mixxx 1.9.0

Bug Description

Based on gprof data, the pushBuffer function in soundmanager.cpp is inefficient. Calls to chanGroup.getChannelCount() and chanGroup.getChannelBase() number in the millions after less than a minute of use. Flipping the loop, to iterate through inputs then frames, instead of frames then inputs, results in massive cpu load reduction.

Related branches

lp:~mixxxdevelopers/mixxx/trunk

Revision history for this message

Owen Williams (ywwg) wrote on 2010-11-29:

patch to flip loop and reduce cpu Edit (3.1 KiB, text/plain)

Revision history for this message

RJ Skerry-Ryan (rryan) wrote on 2010-12-01:

Nice catch Owen! There's an identical loop in SoundDevicePortAudio::callbackProcess and this inversion was done in trunk, but the pushBuffer version of the loop was not done.

I backported your patch to 1.8 (since we're going to do a 1.8.2) and also backported the SoundDevicePortAudio::callbackProcess to lp:mixxx/1.8 as well.