Re: [PATCH v3 0/7] dma-buf: Performance improvements for system heap & a system-uncached implementation

[John Stultz]

On Thu, Oct 8, 2020 at 4:36 AM Brian Starkey <brian.starkey@xxxxxxx> wrote:
>
> Hi John,
>
> On Sat, Oct 03, 2020 at 04:02:50AM +0000, John Stultz wrote:
> > Hey All,
>
> ...
>
> >
> > I did add to this series a reworked version of my uncached
> > system heap implementation I was submitting a few weeks back.
> > Since it duplicated a lot of the now reworked system heap code,
> > I realized it would be much simpler to add the functionality to
> > the system_heap implementaiton itself.
>
> That looks like a neat approach to me. Referencing your previous
> thread, I like the separate heap (as you have done), rather than a
> generic "cached"/"noncached" flag on all heaps.
>

Sounds good! I really appreciate the feedback on this.

> > While not improving the core allocation performance, the
> > uncached heap allocations do result in *much* improved
> > performance on HiKey960 as it avoids a lot of flushing and
> > invalidating buffers that the cpu doesn't touch often.
> >
> > Feedback on these would be great!
>
> Minor nit: s/detatch/detach/ on both heaps, but other than that
> you can add my r-b to patches 1-5.

Doh! Thanks for the spelling catch! Thanks again!

> As you've said, it does feel like there's some room for
> de-duplication, but that will be easier to work out once the
> implementations settle.
>
> I've a couple of comments for the uncached heap, but I'm not confident
> I understand the implications of having the non-cached alias enough to
> say if it looks OK or not.

Thanks so much!
-john