Date: Tue, 23 Oct 2007 19:49:48 +0200 From: Kris Kennaway <kris@FreeBSD.org> To: josh.carroll@gmail.com Cc: remy.nonnenmacher@activnetworks.com, freebsd-performance@freebsd.org Subject: Re: ULE vs. 4BSD in RELENG_7 Message-ID: <471E343C.2040509@FreeBSD.org> In-Reply-To: <8cb6106e0710230902x4edf2c8eu2d912d5de1f5d4a2@mail.gmail.com> References: <8cb6106e0710230902x4edf2c8eu2d912d5de1f5d4a2@mail.gmail.com>
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Josh Carroll wrote: > Hello, > > I posted this to the stable mailing list, as I thought it was > pertinent there, but I think it will get better attention here. So I > apologize in advance for cross-posting if this is a faux pas. :) > > Anyway, in summary, ULE is about 5-6 % slower than 4BSD for two > workloads that I am sensitive to: building world with -j X, and ffmpeg > -threads X. Other benchmarks seem to indicate relatively equal > performance between the two. MySQL, on the other hand, is > significantly faster in ULE. > > I'm trying to understand why ffmpeg and buildworld are slower in ULE > than 4BSD, since it seems to me that ULE was supposed to be the better > scaling scheduler. > > Here is a link to the original thread on the stable mailing list: > > http://lists.freebsd.org/pipermail/freebsd-stable/2007-October/037379.html > > Remy replied with some interesting results for building world between > the two schedulers on an 8-way system. It seems that ULE suffers as > more threads/processes are thrown at it, at least it appears that way > from Remy's data. > > Does anyone have any additional performance tests I can run that might > help indicate where the deficiency is in the ULE scheduler? MySQL > performance is excellent, so I'm wondering if it was tuned to that > particular workload? > > I'm not sure if Remy subscribes to this list, so I am CC'ing him. Hope > you don't mind Remy :) One major difference is that your workload is 100% user. Also you were reporting ULE had more idle time, which looks like a bug since I would expect it be basically 0% idle on such a workload. Kris
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