Messages in this thread | | | Date | Mon, 13 Mar 2006 15:46:09 +1100 | From | Peter Williams <> | Subject | Re: 2.6.16-rc5-mm1 -- strange load balancing problems |
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Peter Williams wrote: > Peter Williams wrote: > >> I'm seeing some strange load balancing problems with this kernel. I >> don't think that they're due to the smpnice patches as I've applied >> them on a standard 2.6.15-rc5 kernel and the problem doesn't happen >> there. >> >> The problem is (as I say) quite strange and (for me) very >> reproducible. I have two programs (aspin and gsmiley) which I use to >> produce CPU hard spinners for testing purposes. What I'm finding is >> that when I start several copies of aspin load balancing goes as >> expected but when I launch several copies of gsmiley they all go to >> the one CPU and stick there like glue. (The most obvious difference >> between the two programs is that aspin is just a command line tool >> while gsmiley is an X windows program that spins a simley face and >> reports its own assessment of the percentage of CPU it's getting.) >> The machine that I've seen this problem is a hyper threading Pentium 4 >> and I suspect that it may be due to the SCHED_MC changes which overlap >> SCHED_SMT a bit. >> >> I'm trying to test this on a non hyper threading machine but the >> machine has crashed (different kernel) while doing the build. I'll >> resume this effort tomorrow but I thought that I should report the >> problem so that others could comment. >> >> Peter >> PS SCHED_MC was configured in but I'll try it without tomorrow and >> report the results. > > > Configuring SCHED_MC to "no" causes this problem to go away.
This problem does not appear to be present in 2.6.16-rc6-mm1.
Peter -- Peter Williams pwil3058@bigpond.net.au
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