On Tue, Nov 10, 2020 at 6:33 PM Ricardo Ribalda <ribalda@xxxxxxxxxxxx> wrote: > > Hi Christoph > > On Tue, Nov 10, 2020 at 10:25 AM Christoph Hellwig <hch@xxxxxx> wrote: > > > > On Mon, Nov 09, 2020 at 03:53:55PM +0100, Ricardo Ribalda wrote: > > > Hi Christoph > > > > > > I have started now to give a try to your patchset. Sorry for the delay. > > > > > > For uvc I have prepared this patch: > > > https://github.com/ribalda/linux/commit/9094fe223fe38f8c8ff21366d893b43cbbdf0113 > > > > > > I have tested successfully in a x86_64 noteboot..., yes I know there > > > is no change for that platform :). > > > I am trying to get hold of an arm device that can run the latest > > > kernel from upstream. > > > > > > On the meanwhile if you could take a look to the patch to verify that > > > this the way that you expect the drivers to use your api I would > > > appreciate it > > > > This looks pretty reaosnable. > > > > Great > Thanks Christoph for taking a look quickly. > Also FYI, I managed to boot an ARM device with that tree. But I could > not test the uvc driver (it was a remote device with no usb device > attached) > > Hopefully I will be able to test it for real this week. > > Any suggestions for how to measure performance difference? Back in time Kieran (+CC) shared a patch to add extra statistics for packet processing and payload assembly, with results of various approaches summarized in a spreadsheet: https://docs.google.com/spreadsheets/d/1uPdbdVcebO9OQ0LQ8hR2LGIEySWgSnGwwhzv7LPXAlU/edit#gid=0 That and just simple CPU usage comparison would be enough. > > Thanks! > > > Note that ifdef CONFIG_DMA_NONCOHERENT in the old code doesn't actually > > work, as that option is an internal thing just for mips and sh.. In what terms it doesn't actually work? Last time I checked some platforms actually defined CONFIG_DMA_NONCOHERENT, so those would instead use the kmalloc() + dma_map() path. I don't have any background on why that was added and whether it needs to be preserved, though. Kieran, Laurent, do you have any insight? Best regards, Tomasz
