Date: Mon, 20 Dec 1999 16:39:58 -0500 From: Rob Ellis <rob@web.net> To: freebsd-questions@FreeBSD.ORG Subject: Re: DMA errors Message-ID: <19991220163958.A38319@web.net> In-Reply-To: <19991220124638.B37447@web.net> References: <19991220124638.B37447@web.net>
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> In the bios, there's a chipset setting for 'IDE Ultra DMA Mode', > which can be set to DISABLED or AUTO; if I set it to AUTO, > with DMA enabled in the kernel (wd flags), I get get regular > errors like this: > > > wd1: DMA failure, DMA status 5<active> > > wd2: DMA failure, DMA status 5<active> It looks like even with the bios 'IDE Ultra DMA Mode' set to DISABLE, performance still improves when I set the DMA flag in the kernel... I didn't think to check that. ;-) rawio shows 'sequential read' numbers about double with kernel DMA enabled, even with the bios setting off. So the bios setting just interferes with the kernel DMA stuff ? Or is it setting UDMA/66...?? Anyway, it seems ok off. ># rawio -v 1 /dev/vinum/rlocal # DMA on (b0ff) >Test ID K/sec /sec %User %Sys %Total >RR anon 2993.3 186 0.1 1.2 1.3 16384 >SR anon 30355.2 1853 1.5 25.1 26.5 16384 ># rawio -v 1 /dev/vinum/rlocal # DMA off (90ff) >Test ID K/sec /sec %User %Sys %Total >RR anon 2901.1 179 0.2 1.0 1.2 16384 >SR anon 14721.8 899 0.4 7.8 8.2 16384 - Rob To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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