From: "Allen Curtis" <acurtis@onz.com>
To: "Arto Vuori" <avuori@ssh.com>
Cc: <linuxppc-embedded@lists.linuxppc.org>
Subject: RE: 8260 IDMA experience?
Date: Mon, 3 Jun 2002 06:20:54 -0700 [thread overview]
Message-ID: <NCBBIINEHIPFGJPLBEIFOEAFDIAA.acurtis@onz.com> (raw)
In-Reply-To: <3CFB620E.9F8643EB@ssh.com>
> I have been using IDMA to transfer data between kernel memory and a
> FPGA. I also did some testing with memory-to-memory transfers and i
> didn't find them to be worth the trouble. Performance ain't that great.
> You probably get more speed by copying with your CPU, though you might
> avoid some cache trashing.
So it works but it may not be as fast as a memcpy(). Sounds like more
testing is required to determine the overall benefit of freeing the
processor.
> I did also notice that when i am doing memory-to-peripheral (or
> vice-versa) transfers, IDMA corrupts simultaneous Ethernet traffic
> unless IDMA is set to low-priority mode. Same might apply for
> memory-to-memory transfers.
What 8260 chip revision are you using? I have found lots of problems when
rev A processors but rev C has been much better.
** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/
next prev parent reply other threads:[~2002-06-03 13:20 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-06-01 3:15 8260 IDMA experience? Allen Curtis
2002-06-03 12:33 ` Arto Vuori
2002-06-03 13:20 ` Allen Curtis [this message]
2002-06-03 13:56 ` Arto Vuori
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