Date: Fri, 22 Sep 2000 10:13:13 +0200 (CEST)
From: Soren Schmidt <sos@freebsd.dk>
To: peter@netplex.com.au (Peter Wemm)
Cc: Stephen.Byan@quantum.com (Stephen Byan), mbendiks@eunet.no ('Marius Bendiksen'), fs@FreeBSD.ORG, sos@FreeBSD.ORG, freeBSD-scsi@FreeBSD.ORG
Subject: Re: disable write caching with softupdates?
Message-ID: <200009220813.KAA38726@freebsd.dk>
In-Reply-To: <200009220757.e8M7vtG46023@netplex.com.au> from Peter Wemm at "Sep 22, 2000 00:57:55 am"
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It seems Peter Wemm wrote: > > Well, I have been toying a bit with this, so far results are just > > timing of a make -j16 buildworld on two IBM DJNA drives (ie no tags) > > with varius setups. > > > > ATA driver "as is": > > 3602.63 real 0.00 user 2865.62 sys > > > > ATA driver with flush cache on "BIO_ORDERED": > > 3964.18 real 0.00 user 2870.09 sys > > > > ATA driver with write cache disabled: > > 4423.30 real 0.00 user 2871.87 sys > > > > So, having the write cache there definitly is a win. > > It is a win only if you do not value your data. I would gladly turn it off. > How do we do this right now? (ie: completely off) Se the patch from yesterday, but I'llcome up with a better one (sysctl) as soon as I get a few hours... > > I'll try this on TWO IBM DTLA drives with tags enabled and see what gives.. > > I'm curious to know if tagged queueing compensates for the loss incurred by > disabling write caching. I'll know later today and will post my findings... -Søren To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-fs" in the body of the message
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