From: Peter Clifton <pcjc2@cam.ac.uk>
To: "intel-gfx@lists.freedesktop.org" <intel-gfx@lists.freedesktop.org>
Subject: Re: FPS performance increase when deliberately spinning the CPU with an unrelated task
Date: Tue, 26 Oct 2010 20:34:34 +0100 [thread overview]
Message-ID: <1288121674.3597.12.camel@pcjc2lap> (raw)
In-Reply-To: <87ocai6ndw.fsf@pollan.anholt.net>
On Mon, 2010-10-25 at 13:14 -0700, Eric Anholt wrote:
I'm taking a bet on memory bandwidth being the constraint for fill
limited applications. glxgears manages 59fps at full screen (minus title
bar), which is 1680x1024, giving a pixel rate of approx 100Mpix/second
(Ignoring over-fill)
Assuming 2 bytes per pixel (ignoring possibility of depth / stencil
writes), that is 200M bytes / second.
Now I don't know what the likely memory bandwidth of the GMCH is, but I
bet with scan out and other activity going on, we'll be pushing it quite
hard to sustain that framerate.
I'm targeting a desired ~15-20fps at nearly full-screen for my circuit
board design app, so I will need to be careful with my code!
This said, some top-range current cards from other manufacturers are
claiming fill-rates in 10s of BILLIONS per second, and memory bandwidth
of 10s up to ~100 GB/sec! (Although it comes with more than half the ram
I have in this laptop, and probably costs about 1/2 - 3/4 what the
laptop did).
--
Peter Clifton
Electrical Engineering Division,
Engineering Department,
University of Cambridge,
9, JJ Thomson Avenue,
Cambridge
CB3 0FA
Tel: +44 (0)7729 980173 - (No signal in the lab!)
Tel: +44 (0)1223 748328 - (Shared lab phone, ask for me)
prev parent reply other threads:[~2010-10-26 19:34 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-10-23 12:02 FPS performance increase when deliberately spinning the CPU with an unrelated task Peter Clifton
2010-10-25 20:11 ` Jesse Barnes
2010-10-25 20:20 ` Jesse Barnes
2010-10-26 0:14 ` Peter Clifton
2010-10-26 0:26 ` Jesse Barnes
2010-10-25 20:14 ` Eric Anholt
2010-10-26 19:34 ` Peter Clifton [this message]
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