From: Daniel Vetter <daniel@ffwll.ch>
To: Rob Clark <robdclark@gmail.com>
Cc: "Rob Clark" <robdclark@chromium.org>,
"Daniel Stone" <daniels@collabora.com>,
"Michel Dänzer" <michel@daenzer.net>,
"Daniel Vetter" <daniel.vetter@ffwll.ch>,
"Intel Graphics Development" <intel-gfx@lists.freedesktop.org>,
"Kevin Wang" <kevin1.wang@amd.com>,
"DRI Development" <dri-devel@lists.freedesktop.org>,
"moderated list:DMA BUFFER SHARING FRAMEWORK"
<linaro-mm-sig@lists.linaro.org>,
"Luben Tuikov" <luben.tuikov@amd.com>,
"Kristian H . Kristensen" <hoegsberg@google.com>,
"Chen Li" <chenli@uniontech.com>,
"ML mesa-dev" <mesa-dev@lists.freedesktop.org>,
"Alex Deucher" <alexander.deucher@amd.com>,
"Daniel Vetter" <daniel.vetter@intel.com>,
"Christian König" <christian.koenig@amd.com>,
"Dennis Li" <Dennis.Li@amd.com>,
"Deepak R Varma" <mh12gx2825@gmail.com>
Subject: Re: [Mesa-dev] [PATCH 01/11] drm/amdgpu: Comply with implicit fencing rules
Date: Fri, 21 May 2021 16:58:12 +0200 [thread overview]
Message-ID: <YKfKhMIRxBybyYrx@phenom.ffwll.local> (raw)
In-Reply-To: <CAF6AEGvr_CWDGgKFTNGQTiApbg=kyOn=uBrRM_H3DO8UBq-W5g@mail.gmail.com>
On Fri, May 21, 2021 at 07:58:57AM -0700, Rob Clark wrote:
> On Fri, May 21, 2021 at 2:10 AM Daniel Vetter <daniel.vetter@ffwll.ch> wrote:
> >
> > - msm is mildly entertaining. It also supports MSM_SUBMIT_NO_IMPLICIT,
> > but because it doesn't use the drm/scheduler it handles fences from
> > the wrong context with a synchronous dma_fence_wait. See
> > submit_fence_sync() leading to msm_gem_sync_object(). Investing into
> > a scheduler might be a good idea.
>
> Yeah, drm/scheduler is (along with a lot of other things) on the TODO
> list. But this isn't quite as bad as it sounds because userspace uses
> a u_queue thread to call the submit ioctl rather than blocking the
> driver. (It also offloads some other work from the driver thread,
> like submit merging to reduce # of ioctls. Coincidentally that
> arrangement was a step towards preparing userspace for some
> hypothetical non-ioctl uapi ;-))
You're also holding a pile of locks, which I expect latest with
multi-engine buffer sharing will be pain. If you push this to the
scheduler then the locks aren't held. Or maybe I've misread the flow, it's
become all a bit a blurr after all these drivers :-)
> OTOH it would be good to move blocking until the system can free
> enough pages to repin bo's out of the ioctl path to better handle some
> memory pressure corner cases without having to be interruptable over a
> lot more of the submit path.. Running chrome+android on devices
> without a lot of memory is fun..
Uh that one needs the userspace thread. Or entirely different semantics of
your ioctl, because you're not allowed to allocate memory once any
dma_fence is visible. So offloading the entire pinning to a submit thread
is no-go.
-Daniel
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
prev parent reply other threads:[~2021-05-21 14:58 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-21 9:09 [PATCH 01/11] drm/amdgpu: Comply with implicit fencing rules Daniel Vetter
2021-05-21 9:09 ` [PATCH 02/11] drm/panfrost: Remove sched_lock Daniel Vetter
2021-05-21 9:32 ` Lucas Stach
2021-05-21 14:49 ` Daniel Vetter
2021-05-21 9:09 ` [PATCH 03/11] drm/panfrost: Use xarray and helpers for depedency tracking Daniel Vetter
2021-06-02 14:06 ` Steven Price
2021-06-02 18:51 ` Daniel Vetter
2021-06-03 7:48 ` Steven Price
2021-05-21 9:09 ` [PATCH 04/11] drm/panfrost: Fix implicit sync Daniel Vetter
2021-05-21 12:22 ` Daniel Stone
2021-05-21 12:28 ` [Linaro-mm-sig] " Christian König
2021-05-21 12:54 ` Daniel Stone
2021-05-21 13:09 ` Christian König
2021-05-21 13:23 ` Daniel Stone
2021-05-21 9:09 ` [PATCH 05/11] drm/atomic-helper: make drm_gem_plane_helper_prepare_fb the default Daniel Vetter
2021-05-21 9:09 ` [PATCH 06/11] drm/<driver>: drm_gem_plane_helper_prepare_fb is now " Daniel Vetter
2021-05-21 9:38 ` Lucas Stach
2021-05-21 12:20 ` Heiko Stübner
2021-05-21 12:22 ` Paul Cercueil
2021-05-21 15:53 ` Jernej Škrabec
2021-05-21 23:18 ` Chun-Kuang Hu
2021-05-23 12:17 ` Martin Blumenstingl
2021-05-24 7:54 ` Tomi Valkeinen
2021-05-28 9:55 ` Philippe CORNU
2021-05-21 9:09 ` [PATCH 07/11] drm/armada: Remove prepare/cleanup_fb hooks Daniel Vetter
2021-05-21 9:09 ` [PATCH 08/11] drm/vram-helpers: Create DRM_GEM_VRAM_PLANE_HELPER_FUNCS Daniel Vetter
2021-05-21 9:33 ` tiantao (H)
2021-05-21 9:09 ` [PATCH 09/11] drm/omap: Follow implicit fencing in prepare_fb Daniel Vetter
2021-05-24 7:53 ` Tomi Valkeinen
2021-05-21 9:09 ` [PATCH 10/11] drm/simple-helper: drm_gem_simple_display_pipe_prepare_fb as default Daniel Vetter
2021-05-25 17:48 ` Noralf Trønnes
2021-05-25 17:53 ` Daniel Vetter
2021-05-21 9:09 ` [PATCH 11/11] drm/tiny: drm_gem_simple_display_pipe_prepare_fb is the default Daniel Vetter
2021-05-21 13:41 ` David Lechner
2021-05-21 14:09 ` Noralf Trønnes
2021-05-25 16:05 ` Daniel Vetter
2021-05-21 14:13 ` Oleksandr Andrushchenko
2021-05-28 0:38 ` Linus Walleij
2021-05-21 9:46 ` [PATCH 01/11] drm/amdgpu: Comply with implicit fencing rules Bas Nieuwenhuizen
2021-05-21 14:37 ` Daniel Vetter
2021-05-21 15:00 ` Bas Nieuwenhuizen
2021-05-21 15:16 ` Daniel Vetter
2021-05-21 18:08 ` [Mesa-dev] " Christian König
2021-05-21 18:31 ` Daniel Vetter
2021-05-22 8:30 ` Christian König
2021-05-25 13:05 ` Daniel Vetter
2021-05-25 15:05 ` Christian König
2021-05-25 15:23 ` Daniel Vetter
2021-05-26 13:32 ` Christian König
2021-05-26 13:51 ` Daniel Vetter
2021-05-21 11:22 ` Christian König
2021-05-21 14:58 ` [Mesa-dev] " Rob Clark
2021-05-21 14:58 ` Daniel Vetter [this message]
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