From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D7CA0C63798 for ; Fri, 20 Nov 2020 06:33:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 685F720637 for ; Fri, 20 Nov 2020 06:33:00 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="ErrXRL+3" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725890AbgKTGdA (ORCPT ); Fri, 20 Nov 2020 01:33:00 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42810 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725788AbgKTGc7 (ORCPT ); Fri, 20 Nov 2020 01:32:59 -0500 Received: from mail-lj1-x243.google.com (mail-lj1-x243.google.com [IPv6:2a00:1450:4864:20::243]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 11EA6C0617A7 for ; Thu, 19 Nov 2020 22:32:59 -0800 (PST) Received: by mail-lj1-x243.google.com with SMTP id o24so8903281ljj.6 for ; Thu, 19 Nov 2020 22:32:58 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=EvWUGbwSraVs6ukN8hay7tuFs9ZWzBKsGVI7NzOXAmE=; b=ErrXRL+3x25mRtwhh7zt139WVEQXpcWhIO+pkABzCPYCtB1/F1TJ5xO0cjBXts7Jdt AZ+Dn2dnBXZBX8QSLrJNkQ+UQhrCs4E4WSnb4SeOMl8jahB9WOuzHmO7evtDCfbedTNj 3eRp6kiT4Xul7pn9Of4iZAKnUeuyk9zCcou1UXctmVqyrN2qqG5CKeoNuABy/VPZibVO p2EJqw1j95oJYmb0r5pxoMXF7yf7tbskVUvCQxIXa4WluMyCwtIkXqJNEHJOCvh1X1mr nDGJMyAZbo9DSS5ZTqG2wTkQQ5zeBUCXAClB7jHnDEcNOtYdLOYIz98eS92FFhGTd7E9 y24g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=EvWUGbwSraVs6ukN8hay7tuFs9ZWzBKsGVI7NzOXAmE=; b=kM6Gso3xpXSB5xxdhzA9PcqD6kHBlJTYDKmmfhYUzHZcAuiN02qNOBomoiWJrZfKIY x7I1zcjOdG2Obgxx4gap5c8fx1Kcab+jKINCMPKu/v+JyleQO9Wu57DFyfaENe6uQP9S kTECoW0QugpWMvID49/Hq5a7UxervRvpp50T0q5+gyHP6tkgUfWs/mDf9quL9gwMJ0OW a8fsdNcKA6UOEE8eKHe043wHTh4Zgb0hBMq4z4rH4EmnOPWnmwR+BUMdruAOfcLlAI7Z Rg8SZmo5Ay9l6Wvax6FXYSlyv3m0ZHQKQORU/IYY7KijToWB6WU8zkx7ZipAdl8slXPz ZUnw== X-Gm-Message-State: AOAM532hBEG9IBoOGTgho75FqqVcWLAUDnXX/ByUbUnZyJqWZFHwRwH3 iiB8IyRcZkAJm/YxfHWnJsbAt8yPeMKLMQjYdt28HA== X-Google-Smtp-Source: ABdhPJxHVBQmsR367b+JT3t3jfLxQaNPSvI2MNIraG8WGvwdHUkM8AV5nQtc5uMcxOeIJlBYOGqONXCRu+VvEYVHl4s= X-Received: by 2002:a2e:b059:: with SMTP id d25mr7732176ljl.304.1605853977149; Thu, 19 Nov 2020 22:32:57 -0800 (PST) MIME-Version: 1.0 References: <20201110034934.70898-1-john.stultz@linaro.org> <20201112093237.GS401619@phenom.ffwll.local> <20201113203933.GT401619@phenom.ffwll.local> In-Reply-To: From: Sumit Semwal Date: Fri, 20 Nov 2020 12:02:45 +0530 Message-ID: Subject: Re: [PATCH v5 0/7] dma-buf: Performance improvements for system heap & a system-uncached implementation To: Daniel Vetter Cc: John Stultz , Christian Koenig , lkml , Liam Mark , Laura Abbott , Brian Starkey , Hridya Valsaraju , Suren Baghdasaryan , Sandeep Patil , Daniel Mentz , Chris Goldsworthy , =?UTF-8?Q?=C3=98rjan_Eide?= , Robin Murphy , Ezequiel Garcia , Simon Ser , James Jones , "open list:DMA BUFFER SHARING FRAMEWORK" , DRI mailing list Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Daniel, On Wed, 18 Nov 2020 at 13:16, Daniel Vetter wrote: > > On Wed, Nov 18, 2020 at 3:40 AM John Stultz wrote: > > On Fri, Nov 13, 2020 at 12:39 PM Daniel Vetter wrote: > > > On Thu, Nov 12, 2020 at 08:11:02PM -0800, John Stultz wrote: > > > > On Thu, Nov 12, 2020 at 1:32 AM Daniel Vetter wrote: > > > > > On Thu, Nov 12, 2020 at 11:09:04AM +0530, Sumit Semwal wrote: > > > > > > On Tue, 10 Nov 2020 at 09:19, John Stultz 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. > > > > > > > > As mentioned in the system-uncached patch: > > > > Pending opensource users of this code include: > > > > * AOSP HiKey960 gralloc: > > > > - https://android-review.googlesource.com/c/device/linaro/hikey/+/1399519 > > > > - Visibly improves performance over the system heap > > > > * AOSP Codec2 (possibly, needs more review): > > > > - https://android-review.googlesource.com/c/platform/frameworks/av/+/1360640/17/media/codec2/vndk/C2DmaBufAllocator.cpp#325 > > > > > > > > Additionally both the HiKey, HiKey960 grallocs and Codec2 are already > > > > able to use the current dmabuf heaps instead of ION. > > > > > > > > So I'm not sure what you mean by limbo, other than it being in a > > > > transition state where the interface is upstream and we're working on > > > > moving vendors to it from ION (which is staged to be dropped in 5.11). > > > > Part of that work is making sure we don't regress the performance > > > > expectations. > > > > > > The mesa thing below, since if we test this with some downstream kernel > > > drivers or at least non-mesa userspace I'm somewhat worried we're just > > > creating a nice split world between the android gfx world and the > > > mesa/linux desktop gfx world. > > > > > > But then that's kinda how android rolls, so *shrug* > > > > > > > > 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). > > > > > > > > Tying it with mesa is a little tough as the grallocs for mesa devices > > > > usually use gbm (gralloc.gbm or gralloc.minigbm). Swapping the > > > > allocation path for dmabuf heaps there gets a little complex as last I > > > > tried that (when trying to get HiKey working with Lima graphics, as > > > > gbm wouldn't allocate the contiguous buffers required by the display), > > > > I ran into issues with the drm_hwcomposer and mesa expecting the gbm > > > > private handle metadata in the buffer when it was passed in. > > > > > > > > But I might take a look at it again. I got a bit lost digging through > > > > the mesa gbm allocation paths last time. > > > > > > > > I'll also try to see if I can find a benchmark for the codec2 code > > > > (using dmabuf heaps with and without the uncached heap) on on db845c > > > > (w/ mesa), as that is already working and I suspect that might be > > > > close to what you're looking for. > > > > > > tbh I think trying to push for this long term is the best we can hope for. > > > > > > Media is also a lot more *meh* since it's deeply fragmented and a lot less > > > of it upstream than on the gles/display side. > > > > > > I think confirming that this at least doesn't horrible blow up on a > > > gralloc/gbm+mesa stack would be useful I think. > > > > Sorry, I'm still a little foggy on precisely what you're suggesting here. > > > > The patch stack I have has already been used with db845c (mesa + > > gbm_grallloc), with the codec2 (sw decoders) using dmabuf heaps. > > So no blowing up there. And I'm working with Hridya to find a > > benchmark for codec2 so we can try to show the performance delta. > > > > However, if you're wanting a dma-buf gralloc implementation with mesa, > > that may be a little tougher to do, but I guess I can give it a go. > > > > Hopefully this will address concerns about the system-uncached heap > > patch (the last two patches in this series)? > > > > In the meantime I hope we can queue the first five patches, as it > > would be nice to get the code rearranging in as there are others > > trying to stage their own heaps, and I'd like to avoid dragging that > > churn out for too long (in addition to improving the allocation > > performance). Those changes have no ABI implications. > > Maybe I'm also misunderstanding what dma-buf heaps is used for in > Android, at least usually. I thought it's used to allocate all the > winsys/shared buffers through gralloc (at least in the blobby stacks), > to handle the allocation constraints problem. In the open stacks we > don't seem to have a platform with both mesa and v4l (or some other > codec) with "interesting" allocations constraints, so no one using > that gralloc+dma-buf heaps combo for what it was meant for. Hence why > I'm a bit vary that we're creating something here which just misses > the point a bit when we try to actually use it (in that glorious > forever-future world where an android platform has enough drivers in > upstream to do so). > > For other "this solves a system problem" we tend to be quite a bit > more picky with the demonstration use case, to make sure we're > actually creating something that solves the problem in reality. > > But it also looks like Android's just not there yet, so *shrug* ... For me, looking at the first 5 patches (listed below, for quick reference), they are only doing code reorganisation and minor updates for already existing heaps, and no ABI change, I am not able to clearly see your objection here. To me, these seem to be required updates that the existing system heap users can benefit from. 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 If we talk about the last two patches - the ones that add system uncached heap, I somewhat agree that we should be able to show the performance gains with this approach (which has been in use on ION and in devices) using dma-buf gralloc or similar. We can discuss the system-uncached heap when the dma-buf gralloc or similar demonstration for performance benefits is done, but I am inclined to push these 5 patches listed above through. Best, Sumit. > -Daniel > -- > Daniel Vetter > Software Engineer, Intel Corporation > http://blog.ffwll.ch