From: Christoph Baumann <baumann@kip.uni-heidelberg.de>
To: linux-kernel@vger.kernel.org
Subject: Problem with DMA buffer (in 2.2.15)
Date: Wed, 21 Feb 2001 18:12:34 +0100 [thread overview]
Message-ID: <20010221181234.D4878@kip.uni-heidelberg.de> (raw)
Hello!
I have the following problem.
A user process wants to talk to a PCI board via DMA. The first step I did was
to resolv the physical addresses of the data in user space. This works fine
when writing to the device. But when reading the buffer isn't allocated
and the physical addresses are resolved to zero. I fixed this with initializing
the buffer. My question is: Is there a faster method to get the kernel to
map all the virtual addresses at once and not each by each? This would
increase the performance enormously (from 33MB/s to [hopefully] 100MB/s).
Christoph
--
**********************************************************
* Christoph Baumann *
* Kirchhoff-Institut für Physik - Uni Heidelberg *
* Mail: baumann@kip.uni-heidelberg.de *
* Phone: ++49-6221-54-4329 *
**********************************************************
next reply other threads:[~2001-02-21 17:13 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-02-21 17:12 Christoph Baumann [this message]
2001-02-22 16:24 Christoph Baumann
2001-02-22 16:38 ` Norbert Roos
2001-02-22 17:20 ` Christoph Baumann
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