Messages in this thread | | | Date | Fri, 22 Nov 2013 13:13:44 +0100 | From | Daniel Lezcano <> | Subject | Re: [RFC PATCH 0/4] sched: remove cpu_load decay. |
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On 11/22/2013 07:37 AM, Alex Shi wrote: > The cpu_load decays on time according past cpu load of rq. New sched_avg decays on tasks' load of time. Now we has 2 kind decay for cpu_load. That is a kind of redundancy. And increase the system load in sched_tick etc. > > This patch trying to remove the cpu_load decay. And fixed a nohz_full bug by the way. > > There are 5 load_idx used for cpu_load in sched_domain. busy_idx and idle_idx are not zero usually, but newidle_idx, wake_idx and forkexec_idx are all zero on every arch. A shortcut to remove cpu_Load decay in the first patch. just one line patch for this change. :) > > I have tested the patchset on my pandaES board, 2 cores ARM Cortex A9. > hackbench thread/pipe performance increased nearly 10% with this patchset! That do surprise me! > > latest kernel 527d1511310a89 + this patchset > hackbench -T -g 10 -f 40 > 23.25" 21.7" > 23.16" 19.99" > 24.24" 21.53" > hackbench -p -g 10 -f 40 > 26.52" 22.48" > 23.89" 24.00" > 25.65" 23.06" > hackbench -P -g 10 -f 40 > 20.14" 19.37" > 19.96" 19.76" > 21.76" 21.54" > > The git tree for this patchset at: > git@github.com:alexshi/power-scheduling.git no-load-idx > Since Fengguang had included this tree into his kernel testing system. and I haven't get a regression report until now. I suppose it is fine for x86 system. > > But anyway, since the scheduler change will effect all archs. and hackbench is only benchmark I found now for this patchset. I'd like to see more testing and talking on this patchset.
Hi Alex,
I tried on my Xeon server (2 x 4 cores) your patchset and got the following result:
kernel a5d6e63323fe7799eb0e6 / + patchset
hackbench -T -s 4096 -l 1000 -g 10 -f 40 27.604 38.556 27.397 38.694 26.695 38.647 25.975 38.528 29.586 38.553 25.956 38.331 27.895 38.472 26.874 38.608 26.836 38.341 28.064 38.626 hackbench -p -s 4096 -l 1000 -g 10 -f 40 34.502 35.489 34.551 35.389 34.027 35.664 34.343 35.418 34.570 35.423 34.386 35.466 34.387 35.486 33.869 35.212 34.600 35.465 34.155 35.235 hackbench -P -s 4096 -l 1000 -g 10 -f 40 39.170 38.794 39.108 38.662 39.056 38.946 39.120 38.668 38.896 38.865 39.109 38.803 39.020 38.946 39.099 38.844 38.820 38.872 38.923 39.337
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