Thanks everyone for your help. In summary it sounds like there are two issues. 1) kqemu explicitly uses sched_lock. I'll see if I can contact the author about fixing this. 2) As much as a 6-7% slowdown on buildworld on dual core machines as compared to 4BSD. I'm not sure if I'm going to do anything about this. Once you get to 4 or 8 cores and -j8 or more they even out with ULE having significantly less system time. I don't know if I want to compromise that for slightly better dual core compile times. This is in the tree for 7.0 now though. I'm very excited to see this happen. Thanks again, Jeff ---------- Forwarded message ---------- Date: Tue, 17 Jul 2007 22:53:24 +0000 (UTC) From: Jeff Roberson <jeff_at_FreeBSD.org> To: src-committers_at_FreeBSD.org, cvs-src_at_FreeBSD.org, cvs-all_at_FreeBSD.org Subject: cvs commit: src/sys/kern sched_ule.c jeff 2007-07-17 22:53:24 UTC FreeBSD src repository Modified files: sys/kern sched_ule.c Log: ULE 3.0: Fine grain scheduler locking and affinity improvements. This has been in development for over 6 months as SCHED_SMP. - Implement one spin lock per thread-queue. Threads assigned to a run-queue point to this lock via td_lock. - Improve the facility for assigning threads to CPUs now that sched_lock contention no longer dominates scheduling decisions on larger SMP machines. - Re-write idle time stealing in an attempt to make it less damaging to general performance. This is still disabled by default. See kern.sched.steal_idle. - Call the long-term load balancer from a callout rather than sched_clock() so there are no locks held. This is disabled by default. See kern.sched.balance. - Parameterize many scheduling decisions via sysctls. Try to document these via sysctl descriptions. - General structural and naming cleanups. - Document each function with comments. Tested by: current_at_ amd64, x86, UP, SMP. Approved by: re Revision Changes Path 1.200 +917 -549 src/sys/kern/sched_ule.cReceived on Tue Jul 17 2007 - 23:28:33 UTC
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