Date: Tue, 17 Jul 2007 15:26:59 -0400 (EDT) From: Wes Morgan <morganw@chemikals.org> To: Jeff Roberson <jroberson@chesapeake.net> Cc: current@freebsd.org Subject: Re: ULE/SCHED_SMP diff for 7.0, buildkernel & thanks. Message-ID: <alpine.BSF.0.999.0707171525370.11761@ibyngvyr.purzvxnyf.bet> In-Reply-To: <20070717114147.J92541@10.0.0.1> References: <20070716233030.D92541@10.0.0.1> <b41c75520707170318r2152b9f0l8d2ec7ea592fe450@mail.gmail.com> <469CACEC.1000103@freebsd.org> <b41c75520707170618o4106de94g57e60d2c93a68329@mail.gmail.com> <576dcbc20707170624kb671fe4ia5ddac21af93eccd@mail.gmail.com> <b41c75520707170636u116aa48fr99dfacc11945c922@mail.gmail.com> <20070717114147.J92541@10.0.0.1>
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On Tue, 17 Jul 2007, Jeff Roberson wrote: > With regards to buildkernel times; I do not want to sacrafice performance on > other benchmarks to improve buildkernel. The problem is that 4BSD is as > agressive as possible at scheduling work on idle cores. This behavior that > helps one buildworld hurts on other, in my opinion, more important > benchmarks. > > For example: http://people.freebsd.org/~jeff/sysbench.png > > ULE is 33% faster than SCHED_4BSD at this mysql test. This is a direct > result of prefering to idle to make more efficient scheduling decisions. ULE > is also faster at various networking benchmarks for similar reasons. > > I also believe that while the real time may be slower on buildworld the > system and user time will be smaller by a degree greater than the delta in > real time. This means that while you're building packages you have a little > more cpu time leftover to handle other tasks. Furthermore, as the number of > cores goes up things start to tip in favor of ULE although this is somewhat > because it's harder for even 4BSD to keep them busy due to disk bandwidth. > > Thanks everyone for testing. Can someone confirm that they have tested with > x86 rather than amd64? I will probably commit later today. Running fine on my core duo x86 so far. Interactivity seems good with a buildworld -j4 going on.
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