Date: Thu, 17 Jun 2004 12:24:33 -0500 From: Jon Noack <noackjr@alumni.rice.edu> To: Robert Watson <rwatson@freebsd.org> Cc: freebsd-current@freebsd.org Subject: Re: Possible Threading problem with -CURRENT / MySQL? Message-ID: <40D1D3D1.9010209@alumni.rice.edu> In-Reply-To: <Pine.NEB.3.96L.1040617085226.13466F-100000@fledge.watson.org> References: <Pine.NEB.3.96L.1040617085226.13466F-100000@fledge.watson.org>
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On 06/17/04 08:00, Robert Watson wrote: > On Thu, 17 Jun 2004, Jon Noack wrote: >> On 06/17/04 01:07, Brad Knowles wrote: >>> At 1:31 AM -0400 2004-06-17, Robert Watson wrote: >>>> - Running with SCHED_4BSD instead of SCHED_ULE >>> >>> This is the only one that really concerns me. This shows that we >>> clearly need more work on ULE. Is there one particular thing >>> that we seem to be tripping up on, or is it a multitude of >>> things? >> >> I think I'll switch to 4BSD until I see more work being done on ULE >> (I read cvs-src as a hobby already so I'll know when to switch >> back). I noticed a performance drop from 5.2.1-p8 (with 4BSD) to >> -CURRENT (with ULE) when I upgraded, but I attributed it to other >> things. However, the system still feels slower than before despite >> having since disabled INVARIANTS, WITNESS, and userspace malloc >> debugging flags. > > ULE seems to do a very good job of scheduling interactive tasks over > other workloads, resulting in a very "snappy" feel on my boxes, > despite heavy CPU load from background builds, etc. The workload I > looked at had no real "interactive" component, although it was a > latency-centric RPC test, so timely hand-off as well as high > throughput would be important. I know that Jeff's measurement work > on ULE had a substantial focus on deadlines -- whether or not ULE was > timely in scheduling tasks, etc, and that he demonstrated that it was > much stronger than most other available schedulers in this area. Well, I switched to 4BSD and noticed this right away. I occasionally get sound hiccups under heavy i/o with ULE [1], but with 4BSD it's a bit ridiculous. There's a PR open about it (can't remember which off the top of my head), but sound will skip and slow down (play at half speed or slower). I know the sound locking is not all it should be, so this may not be a representative test. Regardless, my workstations are back on ULE... Jon [1] Often when using tar or bsdtar. To reproduce: cd /usr/ports/www/firefox; make extract
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