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Date: Sun, 25 Jul 2004 13:05:02 +0200
From: Nesimi Buelbuel <nesimi.buelbuel@gmx.de>
To: linux-kernel <linux-kernel@vger.kernel.org>
Subject: High CPU usage for disk I/O while DMA is enabled
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Hi,

my CPU usage goes up to 100% while copying files from CD to HDD or from
HDD to HDD.
I have enabled DMA successfully on all of my HDD.

<snip>
/dev/hda:
 multcount    =  0 (off)
 IO_support   =  0 (default 16-bit)
 unmaskirq    =  0 (off)
 using_dma    =  1 (on)
 keepsettings =  0 (off)
 readonly     =  0 (off)
 readahead    = 256 (on)
 geometry     = 19929/255/63, sectors = 320173056, start = 0
</snip>

I am experiencing this since my Kernel upgrade from the 2.4.x series to
the current 2.6.7 Kernel.
So DMA is definetely running on my box. But the CPU is utilizing too
much while copying files.

Is there anything that I have forgot to consider in the "new" 2.6.x
Kernel series for DMA settings?

Thanks for any hints!

 -- 
 Nesimi Buelbuel <nesimi.buelbuel@gmx.de>
 PGP-Key-ID: 0x2FAE691C 
 "This World is about to be Destroyed!"