From: Boris Brezillon <boris.brezillon@collabora.com>
To: Rob Herring <robh@kernel.org>
Cc: dri-devel <dri-devel@lists.freedesktop.org>,
Alyssa Rosenzweig <alyssa@rosenzweig.io>,
Steven Price <steven.price@arm.com>
Subject: Re: [PATCH 1/2] drm/panfrost: Allow passing extra information about BOs used by a job
Date: Tue, 17 Sep 2019 09:15:05 +0200 [thread overview]
Message-ID: <20190917091505.267b93d6@collabora.com> (raw)
In-Reply-To: <CAL_JsqLSStbn35SY9nE+SNZMnNyBZ2vP1KMH5aFjFxi6mBw2wQ@mail.gmail.com>
On Mon, 16 Sep 2019 17:20:28 -0500
Rob Herring <robh@kernel.org> wrote:
> On Fri, Sep 13, 2019 at 6:17 AM Boris Brezillon
> <boris.brezillon@collabora.com> wrote:
> >
> > The READ/WRITE flags are particularly useful if we want to avoid
> > serialization of jobs that read from the same BO but never write to it.
>
> Any data on performance differences?
Unfortunately no. When I initially added support for BO flags I thought
it would fix a regression I had on one glmark2 test (ideas), but the
problem ended up being something completely different (overhead of
calling ioctl(WAIT_BO) on already idle BOs).
I just ran glmark2 again, and there doesn't seem to be a noticeable
improvement with those 2 patches applied (and mesa patched to use the
new flags). This being said, the improvement is likely to be workload
dependent, so I wouldn't consider these patches as useless, but I'm
fine putting them on hold until we see a real need.
Maybe Steven has some real use cases that could help outline the
benefit of these patches.
>
> > The NO_IMPLICIT_FENCE might be useful when the user knows the BO is
> > shared but jobs are using different portions of the buffer.
>
> Why don't we add this when it is useful rather than might be?
I don't have a need for that one yet, but etanviv has it in place so I
thought I'd add both at the same time.
Note that it could help us reduce the number of fence returned by
panfrost_job_dependency(), but I'm not sure it makes a difference in
terms of perfs.
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next prev parent reply other threads:[~2019-09-17 7:15 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-13 11:17 [PATCH 1/2] drm/panfrost: Allow passing extra information about BOs used by a job Boris Brezillon
2019-09-13 11:17 ` [PATCH 2/2] drm/panfrost: Extend the bo_wait() ioctl Boris Brezillon
2019-09-13 13:46 ` Steven Price
2019-09-16 12:55 ` Boris Brezillon
2019-09-13 13:44 ` [PATCH 1/2] drm/panfrost: Allow passing extra information about BOs used by a job Steven Price
2019-09-16 12:11 ` Alyssa Rosenzweig
2019-09-16 13:11 ` Boris Brezillon
2019-09-16 22:28 ` Rob Herring
2019-09-16 22:20 ` Rob Herring
2019-09-17 7:15 ` Boris Brezillon [this message]
2019-09-23 13:41 ` Steven Price
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