Re: [PATCH v2 0/5] compaction related commits

From: Vlastimil Babka
Date: Mon Mar 03 2014 - 06:02:18 EST

On 02/14/2014 07:53 AM, Joonsoo Kim wrote:
> changes for v2
> o include more experiment data in cover letter
> o deal with vlastimil's comments mostly about commit description on 4/5
>
> This patchset is related to the compaction.
>
> patch 1 fixes contrary implementation of the purpose of compaction.
> patch 2~4 are for optimization.
> patch 5 is just for clean-up.
>
> I tested this patchset with stress-highalloc benchmark on Mel's mmtest
> and cannot find any regression in terms of success rate. And I find
> much reduced(9%) elapsed time.
>
> Below is the average result of 10 runs on my 4GB quad core system.
>
> compaction-base+ is based on 3.13.0 with Vlastimil's recent fixes.
> compaction-fix+ has this patch series on top of compaction-base+.
>
> Thanks.
>
>
> stress-highalloc
> 3.13.0 3.13.0
> compaction-base+ compaction-fix+
> Success 1 14.10 15.00
> Success 2 20.20 20.00
> Success 3 68.30 73.40
>
> 3.13.0 3.13.0
> compaction-base+ compaction-fix+
> User 3486.02 3437.13
> System 757.92 741.15
> Elapsed 1638.52 1488.32
>
> 3.13.0 3.13.0
> compaction-base+ compaction-fix+
> Minor Faults 172591561 167116621
> Major Faults 984 859
> Swap Ins 743 653
> Swap Outs 3657 3535
> Direct pages scanned 129742 127344
> Kswapd pages scanned 1852277 1817825
> Kswapd pages reclaimed 1838000 1804212
> Direct pages reclaimed 129719 127327
> Kswapd efficiency 98% 98%
> Kswapd velocity 1130.066 1221.296
> Direct efficiency 99% 99%
> Direct velocity 79.367 85.585
> Percentage direct scans 6% 6%
> Zone normal velocity 231.829 246.097
> Zone dma32 velocity 972.589 1055.158
> Zone dma velocity 5.015 5.626
> Page writes by reclaim 6287 6534
> Page writes file 2630 2999
> Page writes anon 3657 3535
> Page reclaim immediate 2187 2080
> Sector Reads 2917808 2877336
> Sector Writes 11477891 11206722
> Page rescued immediate 0 0
> Slabs scanned 2214118 2168524
> Direct inode steals 12181 9788
> Kswapd inode steals 144830 132109
> Kswapd skipped wait 0 0
> THP fault alloc 0 0
> THP collapse alloc 0 0
> THP splits 0 0
> THP fault fallback 0 0
> THP collapse fail 0 0
> Compaction stalls 738 714
> Compaction success 194 207
> Compaction failures 543 507
> Page migrate success 1806083 1464014
> Page migrate failure 0 0
> Compaction pages isolated 3873329 3162974
> Compaction migrate scanned 74594862 59874420
> Compaction free scanned 125888854 110868637
> Compaction cost 2469 1998

FWIW, I've let a machine run the series with individual patches applied
on 3.13 with my compaction patches, so 6 is the end of my series and 7-11 yours:
The average is of 10 runs (in case you wonder how that's done, the success rates are
calculated with a new R support that's pending Mel's merge; system time and vmstats
are currently a hack, but I hope to add R support for them as well, and maybe publish
to github or something if there's interest).

Interestingly, you have a much lower success rate and also much lower compaction cost
and, well, even the benchmark times. Wonder what difference in config or hw causes this.
You seem to have THP disabled, I enabled, but that would be weird to cause this.
Anyway, it seems nothing statistically significant happens here. But the patches make
sense so this is not an argument against them :)

3.13 3.13 3.13 3.13 3.13 3.13
6-nothp 7-nothp 8-nothp 9-nothp 10-nothp 11-nothp
Success 1 Min 30.00 ( 0.00%) 25.00 ( 16.67%) 46.00 (-53.33%) 41.00 (-36.67%) 25.00 ( 16.67%) 44.00 (-46.67%)
Success 1 Mean 45.50 ( 0.00%) 45.20 ( 0.66%) 47.30 ( -3.96%) 46.20 ( -1.54%) 44.60 ( 1.98%) 46.70 ( -2.64%)
Success 1 Max 52.00 ( 0.00%) 52.00 ( 0.00%) 50.00 ( 3.85%) 49.00 ( 5.77%) 53.00 ( -1.92%) 49.00 ( 5.77%)
Success 2 Min 36.00 ( 0.00%) 30.00 ( 16.67%) 46.00 (-27.78%) 42.00 (-16.67%) 25.00 ( 30.56%) 46.00 (-27.78%)
Success 2 Mean 47.70 ( 0.00%) 47.20 ( 1.05%) 49.00 ( -2.73%) 47.80 ( -0.21%) 45.60 ( 4.40%) 48.60 ( -1.89%)
Success 2 Max 56.00 ( 0.00%) 55.00 ( 1.79%) 52.00 ( 7.14%) 51.00 ( 8.93%) 53.00 ( 5.36%) 52.00 ( 7.14%)
Success 3 Min 84.00 ( 0.00%) 84.00 ( 0.00%) 84.00 ( 0.00%) 84.00 ( 0.00%) 83.00 ( 1.19%) 84.00 ( 0.00%)
Success 3 Mean 84.30 ( 0.00%) 85.00 ( -0.83%) 85.40 ( -1.30%) 84.90 ( -0.71%) 84.50 ( -0.24%) 84.80 ( -0.59%)
Success 3 Max 85.00 ( 0.00%) 86.00 ( -1.18%) 87.00 ( -2.35%) 86.00 ( -1.18%) 85.00 ( 0.00%) 85.00 ( 0.00%)

3.13 3.13 3.13 3.13 3.13 3.13
6-nothp 7-nothp 8-nothp 9-nothp 10-nothp 11-nothp
User 6059.77 6161.19 6037.71 6145.80 6157.28 6180.10
System 1034.15 1040.78 1034.66 1037.29 1034.39 1038.79
Elapsed 2132.04 2141.36 2149.86 2128.43 2110.11 2126.12

3.13 3.13 3.13 3.13 3.13 3.13
6-nothp 7-nothp 8-nothp 9-nothp 10-nothp 11-nothp
Minor Faults 252919751 253905255 252187591 253325723 252655233 253489596
Major Faults 637 618 626 619 619 622
Swap Ins 6 4 7 6 10 9
Swap Outs 322 404 339 334 393 367
Direct pages scanned 287033 285148 276390 279039 271468 285491
Kswapd pages scanned 1891892 1893049 1912150 1897328 1890594 1901914
Kswapd pages reclaimed 1889422 1890396 1909624 1894755 1888005 1899281
Direct pages reclaimed 286843 284965 276160 278852 271262 285257
Kswapd efficiency 99% 99% 99% 99% 99% 99%
Kswapd velocity 896.585 883.055 876.040 875.818 893.235 895.381
Direct efficiency 99% 99% 99% 99% 99% 99%
Direct velocity 136.028 133.014 126.626 128.806 128.259 134.403
Percentage direct scans 13% 13% 12% 12% 12% 13%
Zone normal velocity 321.232 316.821 310.244 310.490 320.010 315.868
Zone dma32 velocity 711.380 699.247 692.423 694.134 701.483 713.917
Zone dma velocity 0.000 0.000 0.000 0.000 0.000 0.000
Page writes by reclaim 340.600 440.800 381.300 377.300 429.400 452.400
Page writes file 17 36 41 42 35 84
Page writes anon 322 404 339 334 393 367
Page reclaim immediate 383 470 435 453 491 477
Sector Reads 2984072 3001944 3009073 2985139 2983261 2994914
Sector Writes 12175402 12179276 12145946 12116400 12108622 12113503
Page rescued immediate 0 0 0 0 0 0
Slabs scanned 1773696 1767654 1788134 1774720 1751065 1786291
Direct inode steals 15265 16402 16089 14913 14130 16178
Kswapd inode steals 52119 51160 51969 52261 50276 51807
Kswapd skipped wait 0 0 0 0 0 0
THP fault alloc 99 104 93 96 90 90
THP collapse alloc 559 560 592 585 531 608
THP splits 7 6 5 5 5 5
THP fault fallback 2 0 0 0 0 0
THP collapse fail 12 12 12 12 13 11
Compaction stalls 1528 1574 1613 1580 1507 1537
Compaction success 552 571 594 574 554 579
Compaction failures 975 1003 1018 1006 953 958
Page migrate success 3913572 4071734 4016156 3981713 3944844 3846041
Page migrate failure 0 0 0 0 0 0
Compaction pages isolated 8256377 8608215 8489839 8395767 8316197 8135089
Compaction migrate scanned 155216300 161068938 165093536 158926355 157504384 157996946
Compaction free scanned 348489189 367790502 363524078 358476708 354952212 340442016
Compaction cost 5305 5517 5485 5405 5355 5252
NUMA alloc hit 170245991 170939361 169815871 170557197 170160298 170719930
NUMA alloc miss 0 0 0 0 0 0
NUMA interleave hit 0 0 0 0 0 0
NUMA alloc local 170245991 170939361 169815871 170557197 170160298 170719930
NUMA page range updates 0 0 0 0 0 0
NUMA huge PMD updates 0 0 0 0 0 0
NUMA PTE updates 0 0 0 0 0 0
NUMA hint faults 0 0 0 0 0 0
NUMA hint local faults 0 0 0 0 0 0
NUMA hint local percent 100 100 100 100 100 100
NUMA pages migrated 0 0 0 0 0 0
AutoNUMA cost 0 0 0 0 0 0



>
> Joonsoo Kim (5):
> mm/compaction: disallow high-order page for migration target
> mm/compaction: do not call suitable_migration_target() on every page
> mm/compaction: change the timing to check to drop the spinlock
> mm/compaction: check pageblock suitability once per pageblock
> mm/compaction: clean-up code on success of ballon isolation
>
> mm/compaction.c | 75 ++++++++++++++++++++++++++++---------------------------
> 1 file changed, 38 insertions(+), 37 deletions(-)
>

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