Re: [PATCH v2 0/3] uvc gadget performance issues

[Greg Kroah-Hartman]

On Tue, Oct 11, 2022 at 09:48:08PM +0200, Michael Grzeschik wrote:
> I also have an patch in the queue that will limit the sg support for
> devices with speed > HIGH_SPEED. Because of the overhead of the limited
> transfer payload of 1024*3 Bytes, it is possible that a simple memcpy
> will actually be fast enough. But for that patch I still have to make
> proper measurements. Btw. which USB speed are you transferring with?

For a payload that small, yes a memcpy is almost always faster.  I think
it's only much larger sizes that actually start to help with sg.

Can you submit this change now?  Odds are it will help out a lot of
systems.

thanks,

greg k-h