Re: High CPU usage (up to server hang) under heavy I/O load

From: Alan Cox
Date: Mon Aug 16 2004 - 07:01:55 EST


On Llu, 2004-08-16 at 10:13, Mark Watts wrote:
> Would this also mean that if I stick a 64bit SATA raid card (a 3Ware 8506-4LP
> in this case) into a 32bit pci slot, then I/O is always going to suck badly?
>
> ... cos I do, and I/O sucks :)

Seperate issue.

64bit DMA is 64bit addressing (ie can DMA from above 4GB). 64bit wide
slot is double the speed for transfers. The 3ware 8xxx I thought could
do 64bit addressing although the driver seems to indicate it cannot,
so with over 4Gb it would hurt.

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