Re: [PATCH] WIP! media: uvcvideo: Use dma_alloc_noncontiguos API

2020-11-24 Thread Christoph Hellwig
On Tue, Nov 24, 2020 at 01:01:33PM +0100, Ricardo Ribalda wrote: > I was hoping that you could answer that question :). > > Do you have other use-cases than linux-media in mind? > > I think Sergey wants to experiment also with vb2, to figure out how > much it affects it. > His change will be much

Re: [PATCH] WIP! media: uvcvideo: Use dma_alloc_noncontiguos API

2020-11-24 Thread Ricardo Ribalda
HI Christoph On Tue, Nov 24, 2020 at 12:35 PM Christoph Hellwig wrote: > > On Wed, Nov 18, 2020 at 03:25:46PM +0100, Ricardo Ribalda wrote: > > On architectures where the is no coherent caching such as ARM use the > > dma_alloc_noncontiguos API and handle manually the cache flushing using > > dma

Re: [PATCH] WIP! media: uvcvideo: Use dma_alloc_noncontiguos API

2020-11-24 Thread Christoph Hellwig
On Wed, Nov 18, 2020 at 03:25:46PM +0100, Ricardo Ribalda wrote: > On architectures where the is no coherent caching such as ARM use the > dma_alloc_noncontiguos API and handle manually the cache flushing using > dma_sync_single(). > > With this patch on the affected architectures we can measure u

[PATCH] WIP! media: uvcvideo: Use dma_alloc_noncontiguos API

2020-11-18 Thread Ricardo Ribalda
On architectures where the is no coherent caching such as ARM use the dma_alloc_noncontiguos API and handle manually the cache flushing using dma_sync_single(). With this patch on the affected architectures we can measure up to 20x performance improvement in uvc_video_copy_data_work(). Signed-off