Re: [PATCH V2 0/6] Memory compaction efficiency improvements

From: Joonsoo Kim
Date: Thu Dec 12 2013 - 21:00:26 EST


> >>stress-highalloc
> >> 3.13-rc2 3.13-rc2 3.13-rc2 3.13-rc2 3.13-rc2
> >> 2-thp 3-thp 4-thp 5-thp 6-thp
> >>Success 1 Min 2.00 ( 0.00%) 7.00 (-250.00%) 18.00 (-800.00%) 19.00 (-850.00%) 26.00 (-1200.00%)
> >>Success 1 Mean 19.20 ( 0.00%) 17.80 ( 7.29%) 29.20 (-52.08%) 29.90 (-55.73%) 32.80 (-70.83%)
> >>Success 1 Max 27.00 ( 0.00%) 29.00 ( -7.41%) 35.00 (-29.63%) 36.00 (-33.33%) 37.00 (-37.04%)
> >>Success 2 Min 3.00 ( 0.00%) 8.00 (-166.67%) 21.00 (-600.00%) 21.00 (-600.00%) 32.00 (-966.67%)
> >>Success 2 Mean 19.30 ( 0.00%) 17.90 ( 7.25%) 32.20 (-66.84%) 32.60 (-68.91%) 35.70 (-84.97%)
> >>Success 2 Max 27.00 ( 0.00%) 30.00 (-11.11%) 36.00 (-33.33%) 37.00 (-37.04%) 39.00 (-44.44%)
> >>Success 3 Min 62.00 ( 0.00%) 62.00 ( 0.00%) 85.00 (-37.10%) 75.00 (-20.97%) 64.00 ( -3.23%)
> >>Success 3 Mean 66.30 ( 0.00%) 65.50 ( 1.21%) 85.60 (-29.11%) 83.40 (-25.79%) 83.50 (-25.94%)
> >>Success 3 Max 70.00 ( 0.00%) 69.00 ( 1.43%) 87.00 (-24.29%) 86.00 (-22.86%) 87.00 (-24.29%)
> >>
> >> 3.13-rc2 3.13-rc2 3.13-rc2 3.13-rc2 3.13-rc2
> >> 2-thp 3-thp 4-thp 5-thp 6-thp
> >>User 6547.93 6475.85 6265.54 6289.46 6189.96
> >>System 1053.42 1047.28 1043.23 1042.73 1038.73
> >>Elapsed 1835.43 1821.96 1908.67 1912.74 1956.38
> >
> >Hello, Vlastimil.
> >
> >I have some questions related to your stat, not your patchset,
> >just for curiosity. :)
> >
> >Are these results, "elapsed time" and "vmstat", for Success 3 line scenario?
>
> No that's for the whole test which does the scenarios in succession.
>

Okay!

> >If so, could you show me others?
> >I wonder why thp case consumes more system time rather than no-thp case.
>
> Unfortunately these stats are not that useful as they don't
> distinguish the 3 phases and also include what the background load
> does. They are included just to show that nothing truly dramatic is
> happening.
> So
>
> >And I found that elapsed time has no big difference between both cases,
> >roughly less than 2%. In this situation, do we get more benefits with
> >aggressive allocation like no-thp case?
>
> Elapsed time suffers from the same problem, so it's again hard to
> say how relevant it actually is to the allocator workload and how
> much to background load. It seems that the more successful allocator
> is, the longer elapsed time (in both thp and nothp case). My guess
> is that less memory available for the background load makes it
> progress slower which affects the duration of the test as a whole.
>
> I hope that in case of further compaction patches that would be
> potentially more intrusive to the its design (and not bugfixes and
> simple tweaks to the existing design as this series) I will have a
> more detailed breakdown of what time is spent where.

Okay!

Thanks.
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