On Tue, 2007-10-30 at 08:26 +0100, Ingo Molnar wrote: > * Zhang, Yanmin <[EMAIL PROTECTED]> wrote: > > > sub-bisecting captured patch > > 38ad464d410dadceda1563f36bdb0be7fe4c8938(sched: uniform tunings) > > caused 20% regression of aim7. > > > > The last 10% should be also related to sched parameters, such like > > sysctl_sched_min_granularity. > > ah, interesting. Since you have CONFIG_SCHED_DEBUG enabled, could you > please try to figure out what the best value for > /proc/sys/kernel_sched_latency, /proc/sys/kernel_sched_nr_latency and > /proc/sys/kernel_sched_min_granularity is? > > there's a tuning constraint for kernel_sched_nr_latency: > > - kernel_sched_nr_latency should always be set to > kernel_sched_latency/kernel_sched_min_granularity. (it's not a free > tunable) > > i suspect a good approach would be to double the value of > kernel_sched_latency and kernel_sched_nr_latency in each tuning > iteration, while keeping kernel_sched_min_granularity unchanged. That > will excercise the tuning values of the 2.6.23 kernel as well. I followed your idea to test 2.6.24-rc1. The improvement is slow. When sched_nr_latency=2560 and sched_latency_ns=640000000, the performance is still about 15% less than 2.6.23.
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