Date: Wed, 24 Oct 2007 09:39:29 -0400 From: "Josh Carroll" <josh.carroll@gmail.com> To: "Bruce Evans" <brde@optusnet.com.au> Cc: remy.nonnenmacher@activnetworks.com, Kris Kennaway <kris@freebsd.org>, freebsd-performance@freebsd.org Subject: Re: ULE vs. 4BSD in RELENG_7 Message-ID: <8cb6106e0710240639r20e03ce9w81ed3354338b7395@mail.gmail.com> In-Reply-To: <20071024171915.E84143@delplex.bde.org> References: <8cb6106e0710230902x4edf2c8eu2d912d5de1f5d4a2@mail.gmail.com> <471E343C.2040509@FreeBSD.org> <20071024171915.E84143@delplex.bde.org>
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> 5-6% is a lot. ULE has some tuning for makeworld in -current, which > for me reduced it to less than 1% slower than 4BSD (down from 5-10% > slower), for the case of makeworld -j4 over nfs on a 2-CPU system with > the sources pre-cached on the server and objects on a local file system, > and extensive local tuning of makeworld, nfs and network drivers. I > think the tuning in ULE was mainly for a 2-CPU system, because makeworld > seemed to be very bad under ULE only with 2 CPUs. Apparently, it is also > very bad with more CPUs. There are sysctls to modify the ULE tuning. I found Kris' document here: http://people.freebsd.org/~kris/scaling/mysql.html Which also mentions some ULE tuning. The sched_ule man page doesn't mention what these are. Can someone point me to a document that explains the sysctl tuning I can try? I imagine I would want to tweak one or more of these: kern.sched.preemption: 1 kern.sched.topology: 0 kern.sched.steal_thresh: 2 kern.sched.steal_idle: 1 kern.sched.steal_htt: 1 kern.sched.balance_interval: 133 kern.sched.balance: 1 kern.sched.tryself: 1 kern.sched.affinity: 3 kern.sched.pick_pri: 1 kern.sched.preempt_thresh: 64 kern.sched.interact: 30 kern.sched.slice: 13 But I'm not sure which to try. I did try setting kern.sched.pick_pri to 0, but that hasn't helped the ffmpeg workload at least. Thanks, Josh
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