On Thu, Nov 12, 2020 at 11:09:04AM +0530, Sumit Semwal wrote: > Hi John, > > On Tue, 10 Nov 2020 at 09:19, John Stultz <john.stultz@xxxxxxxxxx> wrote: > > > > Hey All, > > So just wanted to send my last revision of my patch series > > of performance optimizations to the dma-buf system heap. > > Thanks very much for your patches - I think the first 5 patches look good to me. > > I know there was a bit of discussion over adding a new system-uncached > heap v/s using a flag to identify that; I think I prefer the separate > heap idea, but lets ask one last time if any one else has any real > objections to it. > > Daniel, Christian: any comments from your side on this? I do wonder a bit where the userspace stack for this all is, since tuning allocators without a full stack is fairly pointless. dma-buf heaps is a bit in a limbo situation here it feels like. Plus I'm vary of anything related to leaking this kind of stuff beyond the dma-api because dma api maintainers don't like us doing that. But personally no concern on that front really, gpus need this. It's just that we do need solid justification I think if we land this. Hence back to first point. Ideally first point comes in the form of benchmarking on android together with a mesa driver (or mesa + some v4l driver or whatever it takes to actually show the benefits, I have no idea). -Daniel > > I am planning to merge this series to drm-misc this week if I hear no > objections. > > > > This series reworks the system heap to use sgtables, and then > > consolidates the pagelist method from the heap-helpers into the > > CMA heap. After which the heap-helpers logic is removed (as it > > is unused). I'd still like to find a better way to avoid some of > > the logic duplication in implementing the entire dma_buf_ops > > handlers per heap. But unfortunately that code is tied somewhat > > to how the buffer's memory is tracked. As more heaps show up I > > think we'll have a better idea how to best share code, so for > > now I think this is ok. > > > > After this, the series introduces an optimization that > > Ørjan Eide implemented for ION that avoids calling sync on > > attachments that don't have a mapping. > > > > Next, an optimization to use larger order pages for the system > > heap. This change brings us closer to the current performance > > of the ION allocation code (though there still is a gap due > > to ION using a mix of deferred-freeing and page pools, I'll be > > looking at integrating those eventually). > > > > Finally, 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 implementation itself. > > > > 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! > > > > thanks > > -john > > > > New in v5: > > * Added a comment explaining why the order sizes are > > chosen as they are > > > > Cc: Sumit Semwal <sumit.semwal@xxxxxxxxxx> > > Cc: Liam Mark <lmark@xxxxxxxxxxxxxx> > > Cc: Laura Abbott <labbott@xxxxxxxxxx> > > Cc: Brian Starkey <Brian.Starkey@xxxxxxx> > > Cc: Hridya Valsaraju <hridya@xxxxxxxxxx> > > Cc: Suren Baghdasaryan <surenb@xxxxxxxxxx> > > Cc: Sandeep Patil <sspatil@xxxxxxxxxx> > > Cc: Daniel Mentz <danielmentz@xxxxxxxxxx> > > Cc: Chris Goldsworthy <cgoldswo@xxxxxxxxxxxxxx> > > Cc: Ørjan Eide <orjan.eide@xxxxxxx> > > Cc: Robin Murphy <robin.murphy@xxxxxxx> > > Cc: Ezequiel Garcia <ezequiel@xxxxxxxxxxxxx> > > Cc: Simon Ser <contact@xxxxxxxxxxx> > > Cc: James Jones <jajones@xxxxxxxxxx> > > Cc: linux-media@xxxxxxxxxxxxxxx > > Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx > > > > John Stultz (7): > > dma-buf: system_heap: Rework system heap to use sgtables instead of > > pagelists > > dma-buf: heaps: Move heap-helper logic into the cma_heap > > implementation > > dma-buf: heaps: Remove heap-helpers code > > dma-buf: heaps: Skip sync if not mapped > > dma-buf: system_heap: Allocate higher order pages if available > > dma-buf: dma-heap: Keep track of the heap device struct > > dma-buf: system_heap: Add a system-uncached heap re-using the system > > heap > > > > drivers/dma-buf/dma-heap.c | 33 +- > > drivers/dma-buf/heaps/Makefile | 1 - > > drivers/dma-buf/heaps/cma_heap.c | 324 +++++++++++++++--- > > drivers/dma-buf/heaps/heap-helpers.c | 270 --------------- > > drivers/dma-buf/heaps/heap-helpers.h | 53 --- > > drivers/dma-buf/heaps/system_heap.c | 494 ++++++++++++++++++++++++--- > > include/linux/dma-heap.h | 9 + > > 7 files changed, 753 insertions(+), 431 deletions(-) > > delete mode 100644 drivers/dma-buf/heaps/heap-helpers.c > > delete mode 100644 drivers/dma-buf/heaps/heap-helpers.h > > > > -- > > 2.17.1 > > > Thanks much, > > Best, > Sumit. -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch
