2011/10/19 Lu Guanqun <guanqun.lu at intel.com>: > Hi Maarten, > > Thanks for your nice work, I'll take a look. > > According to my test here, it seems soft volume processing doesn't cost > CPU usage too much, instead, it's the resampling that takes much CPU > usage. e.g. one sink input, resampler of speex-float-3 is used, the > general CPU usage is about 4%, when resampler of 'copy' is used (of > course, in this case, the same format of sink input and sink should > match), it drops to less than 1%. > > So should we optimize resampler a little harder? Sure, resampling is by far the most CPU intensive thing pulse does. That's why we have the choice of such a large array of algorithms, so that the user can pick the one that fits his CPU/quality tradeoff best. In general you can assume than these resamplers are already as optimized as possible. Especially for our default speex resampler, I don't expect there's a lot to gain. But if you'd like you could work with that project to see if there are improvements possible. Last week I sent some patches to speed up the trivial resampler, but that is more of a toy-resampler, so not that important. If optimizing the resampling algorithms is hard, the easiest solution is to minimize the amount of resampling we do. Pierre's patches that just got merged are a good example of this. Only without resampling (the copy-resampler, which should be more aptly names noop-resampler, because no copying is done) the CPU usage of the other stuff (svolume, sconv, channel remap, mixing) comes on the radar. Maarten
