Date: Thu, 11 Mar 2004 01:04:03 -0800 (PST) From: Julian Elischer <julian@elischer.org> To: Ian FREISLICH <if@hetzner.co.za> Cc: Kris Kennaway <kris@obsecurity.org> Subject: Re: I like SCHED_4BSD Message-ID: <Pine.BSF.4.21.0403110102190.86067-100000@InterJet.elischer.org> In-Reply-To: <E1B1M0Q-0007Wc-00@hetzner.co.za>
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On Thu, 11 Mar 2004, Ian FREISLICH wrote: > > > > > > On Thu, 11 Mar 2004, Ian FREISLICH wrote: > > > > > > > o Better interactivity -- No mouse jerkiness, no sluggish screen update > s = > > > > when > > > > > switching between virtual desktops, etc. > > > > >=20 > > > > > o Better scheduling! I'm serious here. Watching top under SCHED_ULE, > I'm > > > > > seeing 10, 15, 20 seconds go by where ALL processes are sleeping.=20 > > > > > Processes seem to be spending inordinate amounts of time in the "kser > el" > > > > > state. This, of course, doesn't happen with SCHED_4BSD. > > > > > > > > That this observation may well be bogus, because you're trying to > > > > measure the scheduler using a tool that is itself run by the > > > > scheduler, so the process stats you see may not be representative of > > > > what is really happening on your system. > > > > > > That point is taken, however, on my old SMP box _ULE adds an extra > > > ~5000 seconds of wall clock time to a 'make buildworld -j8' compared > > > to _BSD 'make world -j8'. > > > > > > I did some tests about 3 weeks ago using bind-dlz and postgresql-7.4.1 > > > on this same machine trying libc_r and libkse using both schedulers. > > > ULE results with either thread library were dismal ~.33 that of > > > BSD: ULE gave about 17 authoritive lookups a second with BSD giving > > > about 50. The KSE library only dropped the rate by about 2 lookups > > > per second on both schedulers which is essentially noise, but I had > > > expected an improvement. > > > > Re: KSE.... > > We have not yet begun to fight^H^H^H^H^Hoptimise > > see what happens if you disable the halt on idle > > sysctl machdep.cpu_idle_hlt=0 > > The machine will get hotter but it may affect the outcome.. > > Just curious. > > Do you think that this may also affect ULE? BTW, the CPUs are > already hot because they're continuously running the dnetc client. I don't know about ULE but for 4BSD it can slow down KSE and libthr when work is scheduled to an otherwise idle CPU, > > Ian > > -- > Ian Freislich >
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