Date: Mon, 18 Jun 2001 23:07:36 +0200 From: Erik Trulsson <ertr1013@student.uu.se> To: Rick <rick@geckobot.com> Cc: freebsd-questions@FreeBSD.ORG Subject: Re: Significant Performance Drop during 4.0-4.3 Upgrade Message-ID: <20010618230736.A44631@student.uu.se> In-Reply-To: <01061813442301.17965@trap.geckobot.com> References: <01061813442301.17965@trap.geckobot.com>
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On Mon, Jun 18, 2001 at 01:44:23PM -0700, Rick wrote: > Hi! > > I just upgraded 3 servers from 4.0 to 4.3 FreeBSD using sysinstall, and I > noticed that some rm -r operations seemed a little slow after the upgrade. > > Coincidentally I've been working on an ISAM alternative to B-tree so I have a > bunch of performance benchmarks handy. The results: > > Disk hits are *much* slower after the upgrade. Many times slower, in fact. > I also had Berkley DB benchmarks that I was using for comparison and they too > were heavily impacted. > > For the life of me, I can't figure out what the heck happened! SOFTUPDATES > were off before the upgrade and I didn't change of the disk tuning. I did > tweak my kernel a bit, but nothing should have had this effect-- I just > removed a few things that weren't being used like EISA and some network > cards. When I examine dmesg everything still seems to be recognized as ULTRA > DMA, etc. I've tried putting everything back in my kernel and I've try the > GENERIC kernel with no improvements. > > I've looked through the release notes, etc., and couldn't find anythingd > etailing this problem. Did I miss something? Am I just extra lucky? Yes, you missed one small thing. Write caching for IDE disks were turned off by default in 4.3-RELEASE. It has since been turned back on in 4.3-STABLE on since the performance hit was too big. (The reason it was turned off is that if you have the write-cache turned on can result in serious data-loss if you have a power failure.) You can turn it back on by setting hw.ata.wc=1 from the loader. See the manpages for ata(4) and loader(8) for more information. -- <Insert your favourite quote here.> Erik Trulsson ertr1013@student.uu.se To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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