Date: Mon, 18 Jun 2001 16:42:35 -0700 From: Rick <rick@geckobot.com> To: Erik Trulsson <ertr1013@student.uu.se> Cc: freebsd-questions@FreeBSD.ORG Subject: Re: Significant Performance Drop during 4.0-4.3 Upgrade Message-ID: <01061816423505.17965@trap.geckobot.com> In-Reply-To: <20010618230736.A44631@student.uu.se> References: <01061813442301.17965@trap.geckobot.com> <20010618230736.A44631@student.uu.se>
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Hi Erik- Thanks for responding so quickly! Unless I did something wrong, that didn't seem to do the trick. I sure thought it was going to work, though. I added the following line to /boot/defaults/loader.conf: hw.ata.wc="1" ...and rebooted but the performance hasn't picked up to where it was with FreeBSD 4.0. It may have gone up some-- I haven't been tracking the numbers very closely. By coincidence, one of the three systems was upgraded to FreeBSD 4.3 STABLE instead of RELEASE, and it too shows roughly the same performance metrics. If I didn't do this right, please let me know. Otherwise if you or anyone has other thoughts, I'd be happy to give them a try. Rick BTW- I'm not sure it's worth mentioning, but I still don't see any of this in the 4.3 RELEASE notes... On Monday 18 June 2001 14:07, Erik Trulsson wrote: > 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. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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