From: Rob Clark <robdclark@gmail.com>
To: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: freedreno <freedreno@lists.freedesktop.org>,
linux-arm-msm <linux-arm-msm@vger.kernel.org>,
Intel Graphics Development <intel-gfx@lists.freedesktop.org>,
DRI Development <dri-devel@lists.freedesktop.org>,
Daniel Vetter <daniel.vetter@intel.com>,
Lucas Stach <l.stach@pengutronix.de>
Subject: Re: [Intel-gfx] [PATCH v4 14/18] drm/msm: Don't break exclusive fence ordering
Date: Tue, 13 Jul 2021 09:55:11 -0700 [thread overview]
Message-ID: <CAF6AEGtC0BxABJtSaOmhEt_WKiuptWCHP7g4D5wEaJ4NaEuz4w@mail.gmail.com> (raw)
In-Reply-To: <20210712175352.802687-15-daniel.vetter@ffwll.ch>
On Mon, Jul 12, 2021 at 1:02 PM Daniel Vetter <daniel.vetter@ffwll.ch> wrote:
>
> There's only one exclusive slot, and we must not break the ordering.
>
> Adding a new exclusive fence drops all previous fences from the
> dma_resv. To avoid violating the signalling order we err on the side of
> over-synchronizing by waiting for the existing fences, even if
> userspace asked us to ignore them.
>
> A better fix would be to us a dma_fence_chain or _array like e.g.
> amdgpu now uses, but
> - msm has a synchronous dma_fence_wait for anything from another
> context, so doesn't seem to care much,
> - and it probably makes sense to lift this into dma-resv.c code as a
> proper concept, so that drivers don't have to hack up their own
> solution each on their own.
>
> v2: Improve commit message per Lucas' suggestion.
>
> Cc: Lucas Stach <l.stach@pengutronix.de>
> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
> Cc: Rob Clark <robdclark@gmail.com>
> Cc: Sean Paul <sean@poorly.run>
> Cc: linux-arm-msm@vger.kernel.org
> Cc: freedreno@lists.freedesktop.org
> ---
> drivers/gpu/drm/msm/msm_gem_submit.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/msm/msm_gem_submit.c b/drivers/gpu/drm/msm/msm_gem_submit.c
> index b71da71a3dd8..edd0051d849f 100644
> --- a/drivers/gpu/drm/msm/msm_gem_submit.c
> +++ b/drivers/gpu/drm/msm/msm_gem_submit.c
> @@ -306,7 +306,8 @@ static int submit_fence_sync(struct msm_gem_submit *submit, bool no_implicit)
> return ret;
> }
>
> - if (no_implicit)
> + /* exclusive fences must be ordered */
> + if (no_implicit && !write)
> continue;
In practice, modern userspace (the kind that is more likely to set the
no-implicit flag on every submit) also sets MSM_SUBMIT_BO_WRITE on
every bo, to shave some cpu overhead so I suppose this would not
really hurt anything
Do you know if this is covered in any piglit/etc test?
BR,
-R
>
> ret = msm_gem_sync_object(&msm_obj->base, submit->ring->fctx,
> --
> 2.32.0
>
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next prev parent reply other threads:[~2021-07-13 16:51 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-12 17:53 [Intel-gfx] [PATCH v4 00/18] drm/sched dependency tracking and dma-resv fixes Daniel Vetter
2021-07-12 17:53 ` [Intel-gfx] [PATCH v4 01/18] drm/sched: Split drm_sched_job_init Daniel Vetter
2021-07-12 20:22 ` Emma Anholt
2021-07-13 6:40 ` Christian König
2021-07-13 6:53 ` Daniel Vetter
2021-07-12 17:53 ` [Intel-gfx] [PATCH v4 02/18] drm/sched: Barriers are needed for entity->last_scheduled Daniel Vetter
2021-07-13 6:35 ` Christian König
2021-07-13 6:50 ` Daniel Vetter
2021-07-13 7:25 ` Christian König
2021-07-13 9:10 ` Daniel Vetter
2021-07-13 11:20 ` Christian König
2021-07-13 16:11 ` Andrey Grodzovsky
2021-07-13 16:45 ` Daniel Vetter
2021-07-14 22:12 ` Andrey Grodzovsky
2021-07-15 10:16 ` Daniel Vetter
2021-07-12 17:53 ` [Intel-gfx] [PATCH v4 03/18] drm/sched: Add dependency tracking Daniel Vetter
2021-07-27 11:09 ` Daniel Vetter
2021-07-28 11:28 ` [Intel-gfx] [Linaro-mm-sig] " Christian König
2021-07-28 12:09 ` Daniel Vetter
2021-07-28 12:46 ` Christian König
2021-07-28 15:20 ` Melissa Wen
2021-07-12 17:53 ` [Intel-gfx] [PATCH v4 04/18] drm/sched: drop entity parameter from drm_sched_push_job Daniel Vetter
2021-07-12 17:53 ` [Intel-gfx] [PATCH v4 05/18] drm/sched: improve docs around drm_sched_entity Daniel Vetter
2021-07-12 17:53 ` [Intel-gfx] [PATCH v4 06/18] drm/panfrost: use scheduler dependency tracking Daniel Vetter
2021-07-12 17:53 ` [Intel-gfx] [PATCH v4 07/18] drm/lima: " Daniel Vetter
2021-07-12 17:53 ` [Intel-gfx] [PATCH v4 08/18] drm/v3d: Move drm_sched_job_init to v3d_job_init Daniel Vetter
2021-07-14 9:34 ` Melissa Wen
2021-07-12 17:53 ` [Intel-gfx] [PATCH v4 09/18] drm/v3d: Use scheduler dependency handling Daniel Vetter
2021-07-14 9:37 ` Melissa Wen
2021-07-12 17:53 ` [Intel-gfx] [PATCH v4 10/18] drm/etnaviv: " Daniel Vetter
2021-07-12 17:53 ` [Intel-gfx] [PATCH v4 11/18] drm/gem: Delete gem array fencing helpers Daniel Vetter
2021-07-12 17:53 ` [Intel-gfx] [PATCH v4 12/18] drm/sched: Don't store self-dependencies Daniel Vetter
2021-07-12 17:53 ` [Intel-gfx] [PATCH v4 13/18] drm/sched: Check locking in drm_sched_job_await_implicit Daniel Vetter
2021-07-12 17:53 ` [Intel-gfx] [PATCH v4 14/18] drm/msm: Don't break exclusive fence ordering Daniel Vetter
2021-07-13 16:55 ` Rob Clark [this message]
2021-07-13 16:58 ` Daniel Vetter
2021-07-13 17:46 ` Rob Clark
2021-07-13 17:45 ` Daniel Vetter
2021-07-12 17:53 ` [Intel-gfx] [PATCH v4 15/18] drm/etnaviv: " Daniel Vetter
2021-07-12 17:53 ` [Intel-gfx] [PATCH v4 16/18] drm/i915: delete exclude argument from i915_sw_fence_await_reservation Daniel Vetter
2021-07-12 17:53 ` [Intel-gfx] [PATCH v4 17/18] drm/i915: Don't break exclusive fence ordering Daniel Vetter
2021-07-12 17:53 ` [Intel-gfx] [PATCH v4 18/18] dma-resv: Give the docs a do-over Daniel Vetter
2021-07-12 20:47 ` [Intel-gfx] ✗ Fi.CI.CHECKPATCH: warning for drm/sched dependency tracking and dma-resv fixes (rev3) Patchwork
2021-07-12 21:13 ` [Intel-gfx] ✓ Fi.CI.BAT: success " Patchwork
2021-07-12 23:43 ` [Intel-gfx] ✗ Fi.CI.IGT: failure " Patchwork
2021-07-27 11:51 ` [Intel-gfx] [PATCH v4 00/18] drm/sched dependency tracking and dma-resv fixes Boris Brezillon
2021-07-27 14:47 ` Melissa Wen
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