Messages in this thread |  | | Date | Sun, 27 Jan 2013 10:41:40 +0800 | From | Alex Shi <> | Subject | Re: [patch v4 0/18] sched: simplified fork, release load avg and power awareness scheduling |
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On 01/24/2013 11:07 PM, Alex Shi wrote: > On 01/24/2013 05:44 PM, Borislav Petkov wrote: >> On Thu, Jan 24, 2013 at 11:06:42AM +0800, Alex Shi wrote: >>> Since the runnable info needs 345ms to accumulate, balancing >>> doesn't do well for many tasks burst waking. After talking with Mike >>> Galbraith, we are agree to just use runnable avg in power friendly >>> scheduling and keep current instant load in performance scheduling for >>> low latency. >>> >>> So the biggest change in this version is removing runnable load avg in >>> balance and just using runnable data in power balance. >>> >>> The patchset bases on Linus' tree, includes 3 parts, >>> ** 1, bug fix and fork/wake balancing clean up. patch 1~5, >>> ---------------------- >>> the first patch remove one domain level. patch 2~5 simplified fork/wake >>> balancing, it can increase 10+% hackbench performance on our 4 sockets >>> SNB EP machine. >> >> Ok, I see some benchmarking results here and there in the commit >> messages but since this is touching the scheduler, you probably would >> need to make sure it doesn't introduce performance regressions vs >> mainline with a comprehensive set of benchmarks. >> > > Thanks a lot for your comments, Borislav! :) > > For this patchset, the code will just check current policy, if it is > performance, the code patch will back to original performance code at > once. So there should no performance change on performance policy. > > I once tested the balance policy performance with benchmark > kbuild/hackbench/aim9/dbench/tbench on version 2, only hackbench has a > bit drop ~3%. others have no clear change. > >> And, AFAICR, mainline does by default the 'performance' scheme by >> spreading out tasks to idle cores, so have you tried comparing vanilla >> mainline to your patchset in the 'performance' setting so that you can >> make sure there are no problems there? And not only hackbench or a >> microbenchmark but aim9 (I saw that in a commit message somewhere) and >> whatever else multithreaded benchmark you can get your hands on. >> >> Also, you might want to run it on other machines too, not only SNB :-) > > Anyway I will redo the performance testing on this version again on all > machine. but doesn't expect something change. :)
Just rerun some benchmarks: kbuild, specjbb2005, oltp, tbench, aim9, hackbench, fileio-cfq of sysbench, dbench, aiostress, multhreads loopback netperf. on my core2, nhm, wsm, snb, platforms. no clear performance change found.
I also tested balance policy/powersaving policy with above benchmark, found, the specjbb2005 drop much 30~50% on both of policy whenever with openjdk or jrockit. and hackbench drops a lots with powersaving policy on snb 4 sockets platforms. others has no clear change.
> >> And what about ARM, maybe someone there can run your patchset too? >> >> So, it would be cool to see comprehensive results from all those runs >> and see what the numbers say. >> >> Thanks. >> > >
-- Thanks Alex
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