From: Keith Packard <keithp@keithp.com>
To: Ben Widawsky <ben@bwidawsk.net>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>, intel-gfx@lists.freedesktop.org
Subject: Re: [PATCH] [RFC] drm/i915: read-read semaphore optimization
Date: Tue, 13 Dec 2011 15:22:40 -0800 [thread overview]
Message-ID: <868vmghxa7.fsf@sumi.keithp.com> (raw)
In-Reply-To: <4EE7D68D.1090803@bwidawsk.net>
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On Tue, 13 Dec 2011 14:49:49 -0800, Ben Widawsky <ben@bwidawsk.net> wrote:
> Would we want to keep domain tracking if the HW worked correctly and we
> didn't have to always flush. It seems like a shame to just gut the code
> if it actually could offer a benefit on future generations.
That sounds like premature optimization to me. If we want something
similar on future hardware, we can resurrect the old code and see what
pieces are useful. For now, we're fighting correctness and stability
issues, and given the limited (zero? negative?) performance benefits, we
just need to get to code which works reliably and provides good
performance.
The current code has gotten to the 'piles of kludges on kludges' stage,
which makes it very fragile -- see the regression caused by changing
flushing orders in the VT-d work-around.
--
keith.packard@intel.com
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next prev parent reply other threads:[~2011-12-13 23:21 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-13 3:52 [PATCH] [RFC] drm/i915: read-read semaphore optimization Ben Widawsky
2011-12-13 9:49 ` Chris Wilson
2011-12-13 16:01 ` Daniel Vetter
2011-12-13 16:36 ` Keith Packard
2011-12-13 22:49 ` Ben Widawsky
2011-12-13 23:22 ` Keith Packard [this message]
2011-12-14 1:09 ` Eric Anholt
2011-12-14 3:25 ` Keith Packard
2011-12-13 16:59 ` Chris Wilson
2011-12-13 17:22 ` Eric Anholt
2011-12-13 18:36 ` Ben Widawsky
2012-01-16 21:50 ` Daniel Vetter
2012-01-16 22:20 ` Ben Widawsky
2012-01-17 3:41 ` Eric Anholt
2012-01-17 10:15 ` Daniel Vetter
2012-01-17 17:55 ` Eric Anholt
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