On Tue, 08 Jan 2013 07:50:41 +0100 Marek Szyprowski <m.szyprowski@xxxxxxxxxxx> wrote: > > Couldn't this performance difference be due to the usage of GFP_DMA inside > > the VB2 code, like Federico's new patch series is proposing? > > > > If not, why are there a so large performance penalty? > > Nope, this was caused rather by a very poor CPU access to non-cached (aka > 'coherent') memory and the way the video data has been accessed/read > with CPU. Exactly. Uncached memory *hurts*, especially if you're having to touch it all with the CPU. jon -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
