On 9/17/07, Ingo Molnar <[EMAIL PROTECTED]> wrote: > > * Ingo Molnar <[EMAIL PROTECTED]> wrote: > > > i've meanwhile tested hackbench 90 and the performance difference > > between -ck and -cfs-devel seems to be mostly down to the more precise > > (but slower) sched_clock() introduced in v2.6.23 and to the startup > > penalty of freshly created tasks. > > Rob, another thing i just noticed in your .configs: you have > CONFIG_PREEMPT=y enabled. Would it be possible to get a testrun with > that disabled? That gives the best throughput and context-switch latency > numbers. (CONFIG_PREEMPT might also have preemption artifacts - there's > one report of it having _worse_ desktop latencies on certain hardware > than !CONFIG_PREEMPT.)
I reverted the patch from before since it didn't seem to help. Do you think it may have to do with my system having Hyper-Threading enabled? I should have pointed out before that I don't really have a dual-core system, just a P4 with Hyper-Threading (I loosely used core to refer to processor). Some new numbers for 2.6.23-rc6-cfs-devel (!CONFIG_PREEMPT and bound to single processor) lat_ctx: 15 2.73 16 2.74 17 2.81 18 2.74 19 2.74 20 2.73 21 2.60 22 2.74 23 2.72 24 2.74 25 2.74 hackbench: 80 11.578 81 11.991 82 11.914 83 12.026 84 12.226 85 12.347 86 12.552 87 12.655 88 13.011 89 12.941 90 13.237 pipe-test: 1 9.58 2 9.58 3 9.58 4 9.58 5 9.58 6 9.58 7 9.58 8 9.58 9 9.58 10 9.58 The obligatory graphs: http://www.healthcarelinen.com/misc/benchmarks/BOUND_NOPREEMPT_lat_ctx_benchmark.png http://www.healthcarelinen.com/misc/benchmarks/BOUND_NOPREEMPT_hackbench_benchmark.png http://www.healthcarelinen.com/misc/benchmarks/BOUND_NOPREEMPT_pipe-test_benchmark.png A cursory glance suggests that performance wrt lat_ctx and hackbench has increased (lower numbers), but degraded quite a lot for pipe-test. The numbers for pipe-test are extremely stable though, while the numbers for hackbench are more erratic (which isn't saying much since the original numbers gave nearly a straight line). I'm still willing to try out any more ideas. Regards, Rob - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
