From owner-freebsd-hackers Fri Oct 12 15:22:12 2001 Delivered-To: freebsd-hackers@freebsd.org Received: from navgwout.symantec.com (navgwout.symantec.com [198.6.49.12]) by hub.freebsd.org (Postfix) with ESMTP id 944FA37B40D for ; Fri, 12 Oct 2001 15:22:02 -0700 (PDT) Received: from navgwout.symantec.com (navgwout [198.6.49.12]) by navgwout.symantec.com (8.9.3+Sun/8.9.3) with SMTP id PAA19542 for ; Fri, 12 Oct 2001 15:22:02 -0700 (PDT) Received: from mailer.symantec.com ([198.6.49.176]) by navgwout.symantec.com (NAVGW 2.5.1.13) with SMTP id M2001101215220125236 ; Fri, 12 Oct 2001 15:22:01 -0700 Received: from uscu-smtp02.symantec.com (uscu-smtp02.symantec.com [155.64.74.114]) by mailer.symantec.com (8.9.3+Sun/8.9.3) with ESMTP id PAA29696; Fri, 12 Oct 2001 15:22:01 -0700 (PDT) Subject: Re: Severe I/O Problems To: Cc: freebsd-hackers@FreeBSD.ORG X-Mailer: Lotus Notes Release 5.0.8 June 18, 2001 Message-ID: From: "Jay Rossiter" Date: Fri, 12 Oct 2001 15:19:23 -0700 X-MIMETrack: Serialize by Router on USCU-SMTP02/SYMSMTP(Release 5.0.8 |June 18, 2001) at 10/12/2001 03:14:51 PM MIME-Version: 1.0 Content-type: text/plain; charset=us-ascii Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG This does seem to be doing some good. The beginning of the test run is hovering ~30% CPU. I'll have to wait until it finished before I can see if it effected the overall time, though. Something else that I forgot to mention, is that yesterday I did a profiled run, and the code-time between the two scenarios differs by less than ten minutes. (The in-memory files vs. on disk files) The disk files just take infinitely longer to do anything to. Matthew Jacob com> cc: Subject: Re: Severe I/O Problems 10/12/2001 02:57 PM Please respond to mjacob Hmm. Interesting. What's the state of the ATA write caching bit? (sysctl hw.ata.wc)? If it is set to 1, try setting it to 0 in /boot/loader.conf (e.g., add hw.ata.wc=0 ) to /boot/loader.conf -matt On Fri, 12 Oct 2001, Jay Rossiter wrote: > > Someone on -questions recommended that I forward this over here for > you guys to look at. (I'm not subbed to this list) > > There appear to be a lot of changes that went into the filesystem and I/O > code between 4.3 and 4.4. A little over a week ago I upgraded my 4.3 box > to 4.4-STABLE and immediately I started having I/O slowdown. I do > development and QA on a program that is very I/O bound, but the changes > between 4.3 and 4.4 aren't small enough that I can ignore them. > > A few statistics: > > BSD, P4 1.4GHz, ATA100 drives > - Normal test run on 4.3 was taking ~3 hours. > - Normal test run on 4.4 is taking 15-16 hours. > > P3-800, ATA66 drives, SuSE Linux 7.1: > - Normal test run takes ~4.5 hours. > > UltraSparc 10, Solaris 8, ATA66 drives: > - Normal test run takes ~6 hours. > > As you can see, this jump was just phenomenal. > > I can run these tests on a custom 'ramdrive' and the test run takes 1.5 > hours on BSD. ~4 on Solaris, ~2.5 on Linux. > > Even the RS/6000 I test AIX 4.3 with doesn't take this long, though I don't > have statistics for it. > > It appears that the app gets stuck switching between the getblk and biowr > states in top and ps, and very rarely does it take more than 5% of the CPU. > On all other OS's, and even on 4.3, this app was pegging the CPU while it > did its work. > > Basically.. this all comes down to "What the hell is going on here?!" and > "Are there plans to fix it and did anyone even know there was a problem?" > > --- > Jay Rossiter 503-614-7917 > QA Engineer, Test Lead > Symantec Corp. > > > > > To Unsubscribe: send mail to majordomo@FreeBSD.org > with "unsubscribe freebsd-hackers" in the body of the message > To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message