From: Paul Lalonde <plalonde@telus.net>
To: Fans of the OS Plan 9 from Bell Labs <9fans@9fans.net>
Subject: Re: [9fans] image/memimage speed
Date: Fri, 5 Dec 2008 11:21:34 -0800 [thread overview]
Message-ID: <49397F3E.9070801@telus.net> (raw)
In-Reply-To: <13426df10812051049j40b40b78u4ae74a3fc7df07a3@mail.gmail.com>
Again, you can stream a whole frame buffer reasonably fast - that should
be nearly full-rate; it should be full rate if you pre-fetch with
sufficient advance notice (500-1000 clocks), or DMA. But random access
reads *have* to be slow: you get a stall while the system goes to PCIe
for each cache line you attempt to read from.
Paul
ron minnich wrote:
> On Fri, Dec 5, 2008 at 10:32 AM, Russ Cox <rsc@swtch.com> wrote:
>
>
>> To a first approximation, no one reads directly from video memory.
>>
>
> That is certainly true, but it's been a concern for some time for GPU
> computing, and the chipset folks are paying attention.
>
> ron
>
>
next prev parent reply other threads:[~2008-12-05 19:21 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-11-30 22:00 Iruata Souza
2008-11-30 23:54 ` Iruata Souza
2008-12-01 1:29 ` erik quanstrom
2008-12-01 1:54 ` andrey mirtchovski
2008-12-01 2:35 ` erik quanstrom
2008-12-01 3:30 ` andrey mirtchovski
2008-12-01 6:41 ` Paul Lalonde
2008-12-01 14:19 ` Steve Simon
2008-12-01 14:33 ` erik quanstrom
2008-12-05 6:39 ` ron minnich
2008-12-05 13:35 ` erik quanstrom
2008-12-05 18:27 ` Russ Cox
2008-12-05 18:32 ` Russ Cox
2008-12-05 18:49 ` ron minnich
2008-12-05 19:21 ` Paul Lalonde [this message]
2008-12-05 19:25 ` erik quanstrom
2008-12-05 19:30 ` Paul Lalonde
2008-12-05 19:40 ` erik quanstrom
2008-12-05 20:11 ` ron minnich
2008-12-06 5:52 ` Paul Lalonde
2008-12-07 17:00 ` Aki Nyrhinen
2008-12-07 23:22 ` erik quanstrom
2008-12-08 0:17 ` Aki Nyrhinen
2008-12-01 15:24 plalonde
2008-12-05 5:22 ` sqweek
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