07 Aug, 2014

1 commit

  • Until now, the reporting from trace-vmscan-postprocess.pl is not very
    useful because we cannot directly use this script for checking the
    file/anon ratio of scanning. This patch aims to report respectively the
    number of file/anon pages which were scanned/reclaimed by kswapd or
    direct-reclaim. Sample output is usually something like the following.

    Summary
    Direct reclaims: 8823
    Direct reclaim pages scanned: 2438797
    Direct reclaim file pages scanned: 1315200
    Direct reclaim anon pages scanned: 1123597
    Direct reclaim pages reclaimed: 446139
    Direct reclaim file pages reclaimed: 378668
    Direct reclaim anon pages reclaimed: 67471
    Direct reclaim write file sync I/O: 0
    Direct reclaim write anon sync I/O: 0
    Direct reclaim write file async I/O: 0
    Direct reclaim write anon async I/O: 4240
    Wake kswapd requests: 122310
    Time stalled direct reclaim: 13.78 seconds

    Kswapd wakeups: 25817
    Kswapd pages scanned: 170779115
    Kswapd file pages scanned: 162725123
    Kswapd anon pages scanned: 8053992
    Kswapd pages reclaimed: 129065738
    Kswapd file pages reclaimed: 128500930
    Kswapd anon pages reclaimed: 564808
    Kswapd reclaim write file sync I/O: 0
    Kswapd reclaim write anon sync I/O: 0
    Kswapd reclaim write file async I/O: 36
    Kswapd reclaim write anon async I/O: 730730
    Time kswapd awake: 1015.50 seconds

    Signed-off-by: Chen Yucong
    Cc: Mel Gorman
    Cc: Johannes Weiner
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Chen Yucong
     

04 Jul, 2014

1 commit

  • When using trace-vmscan-postprocess.pl for checking the file/anon rate
    of scanning, we can find that it can not be performed. At the same
    time, the following message will be reported:

    WARNING: Format not as expected for event vmscan/mm_vmscan_lru_isolate
    'file' != 'contig_taken' Fewer fields than expected in format at
    ./trace-vmscan-postprocess.pl line 171, line 76.

    In trace-vmscan-postprocess.pl, (contig_taken, contig_dirty, and
    contig_failed) are be associated respectively to (nr_lumpy_taken,
    nr_lumpy_dirty, and nr_lumpy_failed) for lumpy reclaim. Via commit
    c53919adc045 ("mm: vmscan: remove lumpy reclaim"), lumpy reclaim had
    already been removed by Mel, but the update for
    trace-vmscan-postprocess.pl was missed.

    Signed-off-by: Chen Yucong
    Cc: Mel Gorman
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Chen Yucong
     

24 Jan, 2014

1 commit


01 Nov, 2011

1 commit

  • Change ISOLATE_XXX macro with bitwise isolate_mode_t type. Normally,
    macro isn't recommended as it's type-unsafe and making debugging harder as
    symbol cannot be passed throught to the debugger.

    Quote from Johannes
    " Hmm, it would probably be cleaner to fully convert the isolation mode
    into independent flags. INACTIVE, ACTIVE, BOTH is currently a
    tri-state among flags, which is a bit ugly."

    This patch moves isolate mode from swap.h to mmzone.h by memcontrol.h

    Signed-off-by: Minchan Kim
    Cc: Johannes Weiner
    Cc: KAMEZAWA Hiroyuki
    Cc: KOSAKI Motohiro
    Cc: Mel Gorman
    Cc: Rik van Riel
    Cc: Michal Hocko
    Cc: Andrea Arcangeli
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Minchan Kim
     

23 Dec, 2010

1 commit

  • When correlating ftrace results with /proc/vmstat, I noticed that the
    reporting scripts value for "pages scanned" differed significantly. Both
    values were "right" depending on how you look at it.

    The difference is due to vmstat only counting scanning of the inactive
    list towards pages scanned. The analysis script for the tracepoint counts
    active and inactive list yielding a far higher value than vmstat. The
    resulting scanning/reclaim ratio looks much worse. The tracepoint is ok
    but this patch updates the reporting script so that the report values for
    scanned are similar to vmstat.

    Signed-off-by: Mel Gorman
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Mel Gorman
     

27 Oct, 2010

1 commit

  • There have been numerous reports of stalls that pointed at the problem
    being somewhere in the VM. There are multiple roots to the problems which
    means dealing with any of the root problems in isolation is tricky to
    justify on their own and they would still need integration testing. This
    patch series puts together two different patch sets which in combination
    should tackle some of the root causes of latency problems being reported.

    Patch 1 adds a tracepoint for shrink_inactive_list. For this series, the
    most important results is being able to calculate the scanning/reclaim
    ratio as a measure of the amount of work being done by page reclaim.

    Patch 2 accounts for time spent in congestion_wait.

    Patches 3-6 were originally developed by Kosaki Motohiro but reworked for
    this series. It has been noted that lumpy reclaim is far too aggressive
    and trashes the system somewhat. As SLUB uses high-order allocations, a
    large cost incurred by lumpy reclaim will be noticeable. It was also
    reported during transparent hugepage support testing that lumpy reclaim
    was trashing the system and these patches should mitigate that problem
    without disabling lumpy reclaim.

    Patch 7 adds wait_iff_congested() and replaces some callers of
    congestion_wait(). wait_iff_congested() only sleeps if there is a BDI
    that is currently congested. Patch 8 notes that any BDI being congested
    is not necessarily a problem because there could be multiple BDIs of
    varying speeds and numberous zones. It attempts to track when a zone
    being reclaimed contains many pages backed by a congested BDI and if so,
    reclaimers wait on the congestion queue.

    I ran a number of tests with monitoring on X86, X86-64 and PPC64. Each
    machine had 3G of RAM and the CPUs were

    X86: Intel P4 2-core
    X86-64: AMD Phenom 4-core
    PPC64: PPC970MP

    Each used a single disk and the onboard IO controller. Dirty ratio was
    left at 20. I'm just going to report for X86-64 and PPC64 in a vague
    attempt to keep this report short. Four kernels were tested each based on
    v2.6.36-rc4

    traceonly-v2r2: Patches 1 and 2 to instrument vmscan reclaims and congestion_wait
    lowlumpy-v2r3: Patches 1-6 to test if lumpy reclaim is better
    waitcongest-v2r3: Patches 1-7 to only wait on congestion
    waitwriteback-v2r4: Patches 1-8 to detect when a zone is congested

    nocongest-v1r5: Patches 1-3 for testing wait_iff_congestion
    nodirect-v1r5: Patches 1-10 to disable filesystem writeback for better IO

    The tests run were as follows

    kernbench
    compile-based benchmark. Smoke test performance

    sysbench
    OLTP read-only benchmark. Will be re-run in the future as read-write

    micro-mapped-file-stream
    This is a micro-benchmark from Johannes Weiner that accesses a
    large sparse-file through mmap(). It was configured to run in only
    single-CPU mode but can be indicative of how well page reclaim
    identifies suitable pages.

    stress-highalloc
    Tries to allocate huge pages under heavy load.

    kernbench, iozone and sysbench did not report any performance regression
    on any machine. sysbench did pressure the system lightly and there was
    reclaim activity but there were no difference of major interest between
    the kernels.

    X86-64 micro-mapped-file-stream

    traceonly-v2r2 lowlumpy-v2r3 waitcongest-v2r3 waitwriteback-v2r4
    pgalloc_dma 1639.00 ( 0.00%) 667.00 (-145.73%) 1167.00 ( -40.45%) 578.00 (-183.56%)
    pgalloc_dma32 2842410.00 ( 0.00%) 2842626.00 ( 0.01%) 2843043.00 ( 0.02%) 2843014.00 ( 0.02%)
    pgalloc_normal 0.00 ( 0.00%) 0.00 ( 0.00%) 0.00 ( 0.00%) 0.00 ( 0.00%)
    pgsteal_dma 729.00 ( 0.00%) 85.00 (-757.65%) 609.00 ( -19.70%) 125.00 (-483.20%)
    pgsteal_dma32 2338721.00 ( 0.00%) 2447354.00 ( 4.44%) 2429536.00 ( 3.74%) 2436772.00 ( 4.02%)
    pgsteal_normal 0.00 ( 0.00%) 0.00 ( 0.00%) 0.00 ( 0.00%) 0.00 ( 0.00%)
    pgscan_kswapd_dma 1469.00 ( 0.00%) 532.00 (-176.13%) 1078.00 ( -36.27%) 220.00 (-567.73%)
    pgscan_kswapd_dma32 4597713.00 ( 0.00%) 4503597.00 ( -2.09%) 4295673.00 ( -7.03%) 3891686.00 ( -18.14%)
    pgscan_kswapd_normal 0.00 ( 0.00%) 0.00 ( 0.00%) 0.00 ( 0.00%) 0.00 ( 0.00%)
    pgscan_direct_dma 71.00 ( 0.00%) 134.00 ( 47.01%) 243.00 ( 70.78%) 352.00 ( 79.83%)
    pgscan_direct_dma32 305820.00 ( 0.00%) 280204.00 ( -9.14%) 600518.00 ( 49.07%) 957485.00 ( 68.06%)
    pgscan_direct_normal 0.00 ( 0.00%) 0.00 ( 0.00%) 0.00 ( 0.00%) 0.00 ( 0.00%)
    pageoutrun 16296.00 ( 0.00%) 21254.00 ( 23.33%) 18447.00 ( 11.66%) 20067.00 ( 18.79%)
    allocstall 443.00 ( 0.00%) 273.00 ( -62.27%) 513.00 ( 13.65%) 1568.00 ( 71.75%)

    These are based on the raw figures taken from /proc/vmstat. It's a rough
    measure of reclaim activity. Note that allocstall counts are higher
    because we are entering direct reclaim more often as a result of not
    sleeping in congestion. In itself, it's not necessarily a bad thing.
    It's easier to get a view of what happened from the vmscan tracepoint
    report.

    FTrace Reclaim Statistics: vmscan

    traceonly-v2r2 lowlumpy-v2r3 waitcongest-v2r3 waitwriteback-v2r4
    Direct reclaims 443 273 513 1568
    Direct reclaim pages scanned 305968 280402 600825 957933
    Direct reclaim pages reclaimed 43503 19005 30327 117191
    Direct reclaim write file async I/O 0 0 0 0
    Direct reclaim write anon async I/O 0 3 4 12
    Direct reclaim write file sync I/O 0 0 0 0
    Direct reclaim write anon sync I/O 0 0 0 0
    Wake kswapd requests 187649 132338 191695 267701
    Kswapd wakeups 3 1 4 1
    Kswapd pages scanned 4599269 4454162 4296815 3891906
    Kswapd pages reclaimed 2295947 2428434 2399818 2319706
    Kswapd reclaim write file async I/O 1 0 1 1
    Kswapd reclaim write anon async I/O 59 187 41 222
    Kswapd reclaim write file sync I/O 0 0 0 0
    Kswapd reclaim write anon sync I/O 0 0 0 0
    Time stalled direct reclaim (seconds) 4.34 2.52 6.63 2.96
    Time kswapd awake (seconds) 11.15 10.25 11.01 10.19

    Total pages scanned 4905237 4734564 4897640 4849839
    Total pages reclaimed 2339450 2447439 2430145 2436897
    %age total pages scanned/reclaimed 47.69% 51.69% 49.62% 50.25%
    %age total pages scanned/written 0.00% 0.00% 0.00% 0.00%
    %age file pages scanned/written 0.00% 0.00% 0.00% 0.00%
    Percentage Time Spent Direct Reclaim 29.23% 19.02% 38.48% 20.25%
    Percentage Time kswapd Awake 78.58% 78.85% 76.83% 79.86%

    What is interesting here for nocongest in particular is that while direct
    reclaim scans more pages, the overall number of pages scanned remains the
    same and the ratio of pages scanned to pages reclaimed is more or less the
    same. In other words, while we are sleeping less, reclaim is not doing
    more work and as direct reclaim and kswapd is awake for less time, it
    would appear to be doing less work.

    FTrace Reclaim Statistics: congestion_wait
    Direct number congest waited 87 196 64 0
    Direct time congest waited 4604ms 4732ms 5420ms 0ms
    Direct full congest waited 72 145 53 0
    Direct number conditional waited 0 0 324 1315
    Direct time conditional waited 0ms 0ms 0ms 0ms
    Direct full conditional waited 0 0 0 0
    KSwapd number congest waited 20 10 15 7
    KSwapd time congest waited 1264ms 536ms 884ms 284ms
    KSwapd full congest waited 10 4 6 2
    KSwapd number conditional waited 0 0 0 0
    KSwapd time conditional waited 0ms 0ms 0ms 0ms
    KSwapd full conditional waited 0 0 0 0

    The vanilla kernel spent 8 seconds asleep in direct reclaim and no time at
    all asleep with the patches.

    MMTests Statistics: duration
    User/Sys Time Running Test (seconds) 10.51 10.73 10.6 11.66
    Total Elapsed Time (seconds) 14.19 13.00 14.33 12.76

    Overall, the tests completed faster. It is interesting to note that backing off further
    when a zone is congested and not just a BDI was more efficient overall.

    PPC64 micro-mapped-file-stream
    pgalloc_dma 3024660.00 ( 0.00%) 3027185.00 ( 0.08%) 3025845.00 ( 0.04%) 3026281.00 ( 0.05%)
    pgalloc_normal 0.00 ( 0.00%) 0.00 ( 0.00%) 0.00 ( 0.00%) 0.00 ( 0.00%)
    pgsteal_dma 2508073.00 ( 0.00%) 2565351.00 ( 2.23%) 2463577.00 ( -1.81%) 2532263.00 ( 0.96%)
    pgsteal_normal 0.00 ( 0.00%) 0.00 ( 0.00%) 0.00 ( 0.00%) 0.00 ( 0.00%)
    pgscan_kswapd_dma 4601307.00 ( 0.00%) 4128076.00 ( -11.46%) 3912317.00 ( -17.61%) 3377165.00 ( -36.25%)
    pgscan_kswapd_normal 0.00 ( 0.00%) 0.00 ( 0.00%) 0.00 ( 0.00%) 0.00 ( 0.00%)
    pgscan_direct_dma 629825.00 ( 0.00%) 971622.00 ( 35.18%) 1063938.00 ( 40.80%) 1711935.00 ( 63.21%)
    pgscan_direct_normal 0.00 ( 0.00%) 0.00 ( 0.00%) 0.00 ( 0.00%) 0.00 ( 0.00%)
    pageoutrun 27776.00 ( 0.00%) 20458.00 ( -35.77%) 18763.00 ( -48.04%) 18157.00 ( -52.98%)
    allocstall 977.00 ( 0.00%) 2751.00 ( 64.49%) 2098.00 ( 53.43%) 5136.00 ( 80.98%)

    Similar trends to x86-64. allocstalls are up but it's not necessarily bad.

    FTrace Reclaim Statistics: vmscan
    Direct reclaims 977 2709 2098 5136
    Direct reclaim pages scanned 629825 963814 1063938 1711935
    Direct reclaim pages reclaimed 75550 242538 150904 387647
    Direct reclaim write file async I/O 0 0 0 2
    Direct reclaim write anon async I/O 0 10 0 4
    Direct reclaim write file sync I/O 0 0 0 0
    Direct reclaim write anon sync I/O 0 0 0 0
    Wake kswapd requests 392119 1201712 571935 571921
    Kswapd wakeups 3 2 3 3
    Kswapd pages scanned 4601307 4128076 3912317 3377165
    Kswapd pages reclaimed 2432523 2318797 2312673 2144616
    Kswapd reclaim write file async I/O 20 1 1 1
    Kswapd reclaim write anon async I/O 57 132 11 121
    Kswapd reclaim write file sync I/O 0 0 0 0
    Kswapd reclaim write anon sync I/O 0 0 0 0
    Time stalled direct reclaim (seconds) 6.19 7.30 13.04 10.88
    Time kswapd awake (seconds) 21.73 26.51 25.55 23.90

    Total pages scanned 5231132 5091890 4976255 5089100
    Total pages reclaimed 2508073 2561335 2463577 2532263
    %age total pages scanned/reclaimed 47.95% 50.30% 49.51% 49.76%
    %age total pages scanned/written 0.00% 0.00% 0.00% 0.00%
    %age file pages scanned/written 0.00% 0.00% 0.00% 0.00%
    Percentage Time Spent Direct Reclaim 18.89% 20.65% 32.65% 27.65%
    Percentage Time kswapd Awake 72.39% 80.68% 78.21% 77.40%

    Again, a similar trend that the congestion_wait changes mean that direct
    reclaim scans more pages but the overall number of pages scanned while
    slightly reduced, are very similar. The ratio of scanning/reclaimed
    remains roughly similar. The downside is that kswapd and direct reclaim
    was awake longer and for a larger percentage of the overall workload.
    It's possible there were big differences in the amount of time spent
    reclaiming slab pages between the different kernels which is plausible
    considering that the micro tests runs after fsmark and sysbench.

    Trace Reclaim Statistics: congestion_wait
    Direct number congest waited 845 1312 104 0
    Direct time congest waited 19416ms 26560ms 7544ms 0ms
    Direct full congest waited 745 1105 72 0
    Direct number conditional waited 0 0 1322 2935
    Direct time conditional waited 0ms 0ms 12ms 312ms
    Direct full conditional waited 0 0 0 3
    KSwapd number congest waited 39 102 75 63
    KSwapd time congest waited 2484ms 6760ms 5756ms 3716ms
    KSwapd full congest waited 20 48 46 25
    KSwapd number conditional waited 0 0 0 0
    KSwapd time conditional waited 0ms 0ms 0ms 0ms
    KSwapd full conditional waited 0 0 0 0

    The vanilla kernel spent 20 seconds asleep in direct reclaim and only
    312ms asleep with the patches. The time kswapd spent congest waited was
    also reduced by a large factor.

    MMTests Statistics: duration
    ser/Sys Time Running Test (seconds) 26.58 28.05 26.9 28.47
    Total Elapsed Time (seconds) 30.02 32.86 32.67 30.88

    With all patches applies, the completion times are very similar.

    X86-64 STRESS-HIGHALLOC
    traceonly-v2r2 lowlumpy-v2r3 waitcongest-v2r3waitwriteback-v2r4
    Pass 1 82.00 ( 0.00%) 84.00 ( 2.00%) 85.00 ( 3.00%) 85.00 ( 3.00%)
    Pass 2 90.00 ( 0.00%) 87.00 (-3.00%) 88.00 (-2.00%) 89.00 (-1.00%)
    At Rest 92.00 ( 0.00%) 90.00 (-2.00%) 90.00 (-2.00%) 91.00 (-1.00%)

    Success figures across the board are broadly similar.

    traceonly-v2r2 lowlumpy-v2r3 waitcongest-v2r3waitwriteback-v2r4
    Direct reclaims 1045 944 886 887
    Direct reclaim pages scanned 135091 119604 109382 101019
    Direct reclaim pages reclaimed 88599 47535 47863 46671
    Direct reclaim write file async I/O 494 283 465 280
    Direct reclaim write anon async I/O 29357 13710 16656 13462
    Direct reclaim write file sync I/O 154 2 2 3
    Direct reclaim write anon sync I/O 14594 571 509 561
    Wake kswapd requests 7491 933 872 892
    Kswapd wakeups 814 778 731 780
    Kswapd pages scanned 7290822 15341158 11916436 13703442
    Kswapd pages reclaimed 3587336 3142496 3094392 3187151
    Kswapd reclaim write file async I/O 91975 32317 28022 29628
    Kswapd reclaim write anon async I/O 1992022 789307 829745 849769
    Kswapd reclaim write file sync I/O 0 0 0 0
    Kswapd reclaim write anon sync I/O 0 0 0 0
    Time stalled direct reclaim (seconds) 4588.93 2467.16 2495.41 2547.07
    Time kswapd awake (seconds) 2497.66 1020.16 1098.06 1176.82

    Total pages scanned 7425913 15460762 12025818 13804461
    Total pages reclaimed 3675935 3190031 3142255 3233822
    %age total pages scanned/reclaimed 49.50% 20.63% 26.13% 23.43%
    %age total pages scanned/written 28.66% 5.41% 7.28% 6.47%
    %age file pages scanned/written 1.25% 0.21% 0.24% 0.22%
    Percentage Time Spent Direct Reclaim 57.33% 42.15% 42.41% 42.99%
    Percentage Time kswapd Awake 43.56% 27.87% 29.76% 31.25%

    Scanned/reclaimed ratios again look good with big improvements in
    efficiency. The Scanned/written ratios also look much improved. With a
    better scanned/written ration, there is an expectation that IO would be
    more efficient and indeed, the time spent in direct reclaim is much
    reduced by the full series and kswapd spends a little less time awake.

    Overall, indications here are that allocations were happening much faster
    and this can be seen with a graph of the latency figures as the
    allocations were taking place
    http://www.csn.ul.ie/~mel/postings/vmscanreduce-20101509/highalloc-interlatency-hydra-mean.ps

    FTrace Reclaim Statistics: congestion_wait
    Direct number congest waited 1333 204 169 4
    Direct time congest waited 78896ms 8288ms 7260ms 200ms
    Direct full congest waited 756 92 69 2
    Direct number conditional waited 0 0 26 186
    Direct time conditional waited 0ms 0ms 0ms 2504ms
    Direct full conditional waited 0 0 0 25
    KSwapd number congest waited 4 395 227 282
    KSwapd time congest waited 384ms 25136ms 10508ms 18380ms
    KSwapd full congest waited 3 232 98 176
    KSwapd number conditional waited 0 0 0 0
    KSwapd time conditional waited 0ms 0ms 0ms 0ms
    KSwapd full conditional waited 0 0 0 0
    KSwapd full conditional waited 318 0 312 9

    Overall, the time spent speeping is reduced. kswapd is still hitting
    congestion_wait() but that is because there are callers remaining where it
    wasn't clear in advance if they should be changed to wait_iff_congested()
    or not. Overall the sleep imes are reduced though - from 79ish seconds to
    about 19.

    MMTests Statistics: duration
    User/Sys Time Running Test (seconds) 3415.43 3386.65 3388.39 3377.5
    Total Elapsed Time (seconds) 5733.48 3660.33 3689.41 3765.39

    With the full series, the time to complete the tests are reduced by 30%

    PPC64 STRESS-HIGHALLOC
    traceonly-v2r2 lowlumpy-v2r3 waitcongest-v2r3waitwriteback-v2r4
    Pass 1 17.00 ( 0.00%) 34.00 (17.00%) 38.00 (21.00%) 43.00 (26.00%)
    Pass 2 25.00 ( 0.00%) 37.00 (12.00%) 42.00 (17.00%) 46.00 (21.00%)
    At Rest 49.00 ( 0.00%) 43.00 (-6.00%) 45.00 (-4.00%) 51.00 ( 2.00%)

    Success rates there are *way* up particularly considering that the 16MB
    huge pages on PPC64 mean that it's always much harder to allocate them.

    FTrace Reclaim Statistics: vmscan
    stress-highalloc stress-highalloc stress-highalloc stress-highalloc
    traceonly-v2r2 lowlumpy-v2r3 waitcongest-v2r3waitwriteback-v2r4
    Direct reclaims 499 505 564 509
    Direct reclaim pages scanned 223478 41898 51818 45605
    Direct reclaim pages reclaimed 137730 21148 27161 23455
    Direct reclaim write file async I/O 399 136 162 136
    Direct reclaim write anon async I/O 46977 2865 4686 3998
    Direct reclaim write file sync I/O 29 0 1 3
    Direct reclaim write anon sync I/O 31023 159 237 239
    Wake kswapd requests 420 351 360 326
    Kswapd wakeups 185 294 249 277
    Kswapd pages scanned 15703488 16392500 17821724 17598737
    Kswapd pages reclaimed 5808466 2908858 3139386 3145435
    Kswapd reclaim write file async I/O 159938 18400 18717 13473
    Kswapd reclaim write anon async I/O 3467554 228957 322799 234278
    Kswapd reclaim write file sync I/O 0 0 0 0
    Kswapd reclaim write anon sync I/O 0 0 0 0
    Time stalled direct reclaim (seconds) 9665.35 1707.81 2374.32 1871.23
    Time kswapd awake (seconds) 9401.21 1367.86 1951.75 1328.88

    Total pages scanned 15926966 16434398 17873542 17644342
    Total pages reclaimed 5946196 2930006 3166547 3168890
    %age total pages scanned/reclaimed 37.33% 17.83% 17.72% 17.96%
    %age total pages scanned/written 23.27% 1.52% 1.94% 1.43%
    %age file pages scanned/written 1.01% 0.11% 0.11% 0.08%
    Percentage Time Spent Direct Reclaim 44.55% 35.10% 41.42% 36.91%
    Percentage Time kswapd Awake 86.71% 43.58% 52.67% 41.14%

    While the scanning rates are slightly up, the scanned/reclaimed and
    scanned/written figures are much improved. The time spent in direct
    reclaim and with kswapd are massively reduced, mostly by the lowlumpy
    patches.

    FTrace Reclaim Statistics: congestion_wait
    Direct number congest waited 725 303 126 3
    Direct time congest waited 45524ms 9180ms 5936ms 300ms
    Direct full congest waited 487 190 52 3
    Direct number conditional waited 0 0 200 301
    Direct time conditional waited 0ms 0ms 0ms 1904ms
    Direct full conditional waited 0 0 0 19
    KSwapd number congest waited 0 2 23 4
    KSwapd time congest waited 0ms 200ms 420ms 404ms
    KSwapd full congest waited 0 2 2 4
    KSwapd number conditional waited 0 0 0 0
    KSwapd time conditional waited 0ms 0ms 0ms 0ms
    KSwapd full conditional waited 0 0 0 0

    Not as dramatic a story here but the time spent asleep is reduced and we
    can still see what wait_iff_congested is going to sleep when necessary.

    MMTests Statistics: duration
    User/Sys Time Running Test (seconds) 12028.09 3157.17 3357.79 3199.16
    Total Elapsed Time (seconds) 10842.07 3138.72 3705.54 3229.85

    The time to complete this test goes way down. With the full series, we
    are allocating over twice the number of huge pages in 30% of the time and
    there is a corresponding impact on the allocation latency graph available
    at.

    http://www.csn.ul.ie/~mel/postings/vmscanreduce-20101509/highalloc-interlatency-powyah-mean.ps

    This patch:

    Add a trace event for shrink_inactive_list() and updates the sample
    postprocessing script appropriately. It can be used to determine how many
    pages were reclaimed and for non-lumpy reclaim where exactly the pages
    were reclaimed from.

    Signed-off-by: Mel Gorman
    Cc: Johannes Weiner
    Cc: Minchan Kim
    Cc: Wu Fengguang
    Cc: KAMEZAWA Hiroyuki
    Cc: KOSAKI Motohiro
    Cc: Rik van Riel
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Mel Gorman
     

10 Aug, 2010

1 commit

  • Add a simple post-processing script for the reclaim-related trace events.
    It can be used to give an indication of how much traffic there is on the
    LRU lists and how severe latencies due to reclaim are. Example output
    looks like the following

    Reclaim latencies expressed as order-latency_in_ms
    uname-3942 9-200.179000000004 9-98.7900000000373 9-99.8330000001006
    kswapd0-311 0-662.097999999998 0-2.79700000002049 \
    0-149.100000000035 0-3295.73600000003 0-9806.31799999997 0-35528.833 \
    0-10043.197 0-129740.979 0-3.50500000000466 0-3.54899999999907 \
    0-9297.78999999992 0-3.48499999998603 0-3596.97999999998 0-3.92799999995623 \
    0-3.35000000009313 0-16729.017 0-3.57799999997951 0-47435.0630000001 \
    0-3.7819999998901 0-5864.06999999995 0-18635.334 0-10541.289 9-186011.565 \
    9-3680.86300000001 9-1379.06499999994 9-958571.115 9-66215.474 \
    9-6721.14699999988 9-1962.15299999993 9-1094806.125 9-2267.83199999994 \
    9-47120.9029999999 9-427653.886 9-2.6359999999404 9-632.148999999976 \
    9-476.753000000026 9-495.577000000048 9-8.45900000003166 9-6.6820000000298 \
    9-1.30500000016764 9-251.746000000043 9-383.905000000028 9-80.1419999999925 \
    9-281.160000000149 9-14.8780000000261 9-381.45299999998 9-512.07799999998 \
    9-49.5519999999087 9-167.439000000013 9-183.820999999996 9-239.527999999933 \
    9-19.9479999998584 9-148.747999999905 9-164.583000000101 9-16.9480000000913 \
    9-192.376000000164 9-64.1010000000242 9-1.40800000005402 9-3.60800000000745 \
    9-17.1359999999404 9-4.69500000006519 9-2.06400000001304 9-1582488.554 \
    9-6244.19499999983 9-348153.812 9-2.0999999998603 9-0.987999999895692 \
    0-32218.473 0-1.6140000000596 0-1.28100000019185 0-1.41300000017509 \
    0-1.32299999985844 0-602.584000000032 0-1.34400000004098 0-1.6929999999702 \
    1-22101.8190000001 9-174876.724 9-16.2420000000857 9-175.165999999736 \
    9-15.8589999997057 9-0.604999999981374 9-3061.09000000032 9-479.277000000235 \
    9-1.54499999992549 9-771.985000000335 9-4.88700000010431 9-15.0649999999441 \
    9-0.879999999888241 9-252.01500000013 9-1381.03600000031 9-545.689999999944 \
    9-3438.0129999998 9-3343.70099999988
    bench-stresshig-3942 9-7063.33900000004 9-129960.482 9-2062.27500000002 \
    9-3845.59399999992 9-171.82799999998 9-16493.821 9-7615.23900000006 \
    9-10217.848 9-983.138000000035 9-2698.39999999991 9-4016.1540000001 \
    9-5522.37700000009 9-21630.429 \
    9-15061.048 9-10327.953 9-542.69700000016 9-317.652000000002 \
    9-8554.71699999995 9-1786.61599999992 9-1899.31499999994 9-2093.41899999999 \
    9-4992.62400000007 9-942.648999999976 9-1923.98300000001 9-3.7980000001844 \
    9-5.99899999983609 9-0.912000000011176 9-1603.67700000014 9-1.98300000000745 \
    9-3.96500000008382 9-0.902999999932945 9-2802.72199999983 9-1078.24799999991 \
    9-2155.82900000014 9-10.058999999892 9-1984.723 9-1687.97999999998 \
    9-1136.05300000007 9-3183.61699999985 9-458.731000000145 9-6.48600000003353 \
    9-1013.25200000009 9-8415.22799999989 9-10065.584 9-2076.79600000009 \
    9-3792.65699999989 9-71.2010000001173 9-2560.96999999997 9-2260.68400000012 \
    9-2862.65799999982 9-1255.81500000018 9-15.7440000001807 9-4.33499999996275 \
    9-1446.63800000004 9-238.635000000009 9-60.1790000000037 9-4.38800000003539 \
    9-639.567000000039 9-306.698000000091 9-31.4070000001229 9-74.997999999905 \
    9-632.725999999791 9-1625.93200000003 9-931.266000000061 9-98.7749999999069 \
    9-984.606999999844 9-225.638999999966 9-421.316000000108 9-653.744999999879 \
    9-572.804000000004 9-769.158999999985 9-603.918000000063 9-4.28499999991618 \
    9-626.21399999992 9-1721.25 9-0.854999999981374 9-572.39599999995 \
    9-681.881999999983 9-1345.12599999993 9-363.666999999899 9-3823.31099999999 \
    9-2991.28200000012 9-4.27099999994971 9-309.76500000013 9-3068.35700000008 \
    9-788.25 9-3515.73999999999 9-2065.96100000013 9-286.719999999972 \
    9-316.076000000117 9-344.151000000071 9-2.51000000000931 9-306.688000000082 \
    9-1515.00099999993 9-336.528999999864 9-793.491999999853 9-457.348999999929 \
    9-13620.155 9-119.933999999892 9-35.0670000000391 9-918.266999999993 \
    9-828.569000000134 9-4863.81099999999 9-105.222000000067 9-894.23900000006 \
    9-110.964999999851 9-0.662999999942258 9-12753.3150000002 9-12.6129999998957 \
    9-13368.0899999999 9-12.4199999999255 9-1.00300000002608 9-1.41100000008009 \
    9-10300.5290000001 9-16.502000000095 9-30.7949999999255 9-6283.0140000002 \
    9-4320.53799999994 9-6826.27300000004 9-3.07299999985844 9-1497.26799999992 \
    9-13.4040000000969 9-3.12999999988824 9-3.86100000003353 9-11.3539999998175 \
    9-0.10799999977462 9-21.780999999959 9-209.695999999996 9-299.647000000114 \
    9-6.01699999999255 9-20.8349999999627 9-22.5470000000205 9-5470.16800000006 \
    9-7.60499999998137 9-0.821000000229105 9-1.56600000010803 9-14.1669999998994 \
    9-0.209000000031665 9-1.82300000009127 9-1.70000000018626 9-19.9429999999702 \
    9-124.266999999993 9-0.0389999998733401 9-6.71400000015274 9-16.7710000001825 \
    9-31.0409999999683 9-0.516999999992549 9-115.888000000035 9-5.19900000002235 \
    9-222.389999999898 9-11.2739999999758 9-80.9050000000279 9-8.14500000001863 \
    9-4.44599999999627 9-0.218999999808148 9-0.715000000083819 9-0.233000000007451
    \
    9-48.2630000000354 9-248.560999999987 9-374.96800000011 9-644.179000000004 \
    9-0.835999999893829 9-79.0060000000522 9-128.447999999858 9-0.692000000039116 \
    9-5.26500000013039 9-128.449000000022 9-2.04799999995157 9-12.0990000001621 \
    9-8.39899999997579 9-10.3860000001732 9-11.9310000000987 9-53.4450000000652 \
    9-0.46999999997206 9-2.96299999998882 9-17.9699999999721 9-0.776000000070781 \
    9-25.2919999998994 9-33.1110000000335 9-0.434000000124797 9-0.641000000061467 \
    9-0.505000000121072 9-1.12800000002608 9-149.222000000067 9-1.17599999997765 \
    9-3247.33100000001 9-10.7439999999478 9-153.523000000045 9-1.38300000014715 \
    9-794.762000000104 9-3.36199999996461 9-128.765999999829 9-181.543999999994 \
    9-78149.8229999999 9-176.496999999974 9-89.9940000001807 9-9.12700000009499 \
    9-250.827000000048 9-0.224999999860302 9-0.388999999966472 9-1.16700000036508 \
    9-32.1740000001155 9-12.6800000001676 9-0.0720000001601875 9-0.274999999906868
    \
    9-0.724000000394881 9-266.866000000387 9-45.5709999999963 9-4.54399999976158 \
    9-8.27199999988079 9-4.38099999958649 9-0.512000000104308 9-0.0640000002458692
    \
    9-5.20000000018626 9-0.0839999997988343 9-12.816000000108 9-0.503000000026077 \
    9-0.507999999914318 9-6.23999999975786 9-3.35100000025705 9-18.8530000001192 \
    9-25.2220000000671 9-68.2309999996796 9-98.9939999999478 9-0.441000000108033 \
    9-4.24599999981001 9-261.702000000048 9-3.01599999982864 9-0.0749999997206032 \
    9-0.0370000000111759 9-4.375 9-3.21800000034273 9-11.3960000001825 \
    9-0.0540000000037253 9-0.286000000312924 9-0.865999999921769 \
    9-0.294999999925494 9-6.45999999996275 9-4.31099999975413 9-128.248999999836 \
    9-0.282999999821186 9-102.155000000261 9-0.0860000001266599 \
    9-0.0540000000037253 9-0.935000000055879 9-0.0670000002719462 \
    9-5.8640000000596 9-19.9860000000335 9-4.18699999991804 9-0.566000000108033 \
    9-2.55099999997765 9-0.702000000048429 9-131.653999999631 9-0.638999999966472 \
    9-14.3229999998584 9-183.398000000045 9-178.095999999903 9-3.22899999981746 \
    9-7.31399999978021 9-22.2400000002235 9-11.7979999999516 9-108.10599999968 \
    9-99.0159999998286 9-102.640999999829 9-38.414000000339
    Process Direct Wokeup Pages Pages Pages
    details Rclms Kswapd Scanned Sync-IO ASync-IO
    cc1-30800 0 1 0 0 0 wakeup-0=1
    cc1-24260 0 1 0 0 0 wakeup-0=1
    cc1-24152 0 12 0 0 0 wakeup-0=12
    cc1-8139 0 1 0 0 0 wakeup-0=1
    cc1-4390 0 1 0 0 0 wakeup-0=1
    cc1-4648 0 7 0 0 0 wakeup-0=7
    cc1-4552 0 3 0 0 0 wakeup-0=3
    dd-4550 0 31 0 0 0 wakeup-0=31
    date-4898 0 1 0 0 0 wakeup-0=1
    cc1-6549 0 7 0 0 0 wakeup-0=7
    as-22202 0 17 0 0 0 wakeup-0=17
    cc1-6495 0 9 0 0 0 wakeup-0=9
    cc1-8299 0 1 0 0 0 wakeup-0=1
    cc1-6009 0 1 0 0 0 wakeup-0=1
    cc1-2574 0 2 0 0 0 wakeup-0=2
    cc1-30568 0 1 0 0 0 wakeup-0=1
    cc1-2679 0 6 0 0 0 wakeup-0=6
    sh-13747 0 12 0 0 0 wakeup-0=12
    cc1-22193 0 18 0 0 0 wakeup-0=18
    cc1-30725 0 2 0 0 0 wakeup-0=2
    as-4392 0 2 0 0 0 wakeup-0=2
    cc1-28180 0 14 0 0 0 wakeup-0=14
    cc1-13697 0 2 0 0 0 wakeup-0=2
    cc1-22207 0 8 0 0 0 wakeup-0=8
    cc1-15270 0 179 0 0 0 wakeup-0=179
    cc1-22011 0 82 0 0 0 wakeup-0=82
    cp-14682 0 1 0 0 0 wakeup-0=1
    as-11926 0 2 0 0 0 wakeup-0=2
    cc1-6016 0 5 0 0 0 wakeup-0=5
    make-18554 0 13 0 0 0 wakeup-0=13
    cc1-8292 0 12 0 0 0 wakeup-0=12
    make-24381 0 1 0 0 0 wakeup-1=1
    date-18681 0 33 0 0 0 wakeup-0=33
    cc1-32276 0 1 0 0 0 wakeup-0=1
    timestamp-outpu-2809 0 253 0 0 0 wakeup-0=240 wakeup-1=13
    date-18624 0 7 0 0 0 wakeup-0=7
    cc1-30960 0 9 0 0 0 wakeup-0=9
    cc1-4014 0 1 0 0 0 wakeup-0=1
    cc1-30706 0 22 0 0 0 wakeup-0=22
    uname-3942 4 1 306 0 17 direct-9=4 wakeup-9=1
    cc1-28207 0 1 0 0 0 wakeup-0=1
    cc1-30563 0 9 0 0 0 wakeup-0=9
    cc1-22214 0 10 0 0 0 wakeup-0=10
    cc1-28221 0 11 0 0 0 wakeup-0=11
    cc1-28123 0 6 0 0 0 wakeup-0=6
    kswapd0-311 0 7 357302 0 34233 wakeup-0=7
    cc1-5988 0 7 0 0 0 wakeup-0=7
    as-30734 0 161 0 0 0 wakeup-0=161
    cc1-22004 0 45 0 0 0 wakeup-0=45
    date-4590 0 4 0 0 0 wakeup-0=4
    cc1-15279 0 213 0 0 0 wakeup-0=213
    date-30735 0 1 0 0 0 wakeup-0=1
    cc1-30583 0 4 0 0 0 wakeup-0=4
    cc1-32324 0 2 0 0 0 wakeup-0=2
    cc1-23933 0 3 0 0 0 wakeup-0=3
    cc1-22001 0 36 0 0 0 wakeup-0=36
    bench-stresshig-3942 287 287 80186 6295 12196 direct-9=287 wakeup-9=287
    cc1-28170 0 7 0 0 0 wakeup-0=7
    date-7932 0 92 0 0 0 wakeup-0=92
    cc1-22222 0 6 0 0 0 wakeup-0=6
    cc1-32334 0 16 0 0 0 wakeup-0=16
    cc1-2690 0 6 0 0 0 wakeup-0=6
    cc1-30733 0 9 0 0 0 wakeup-0=9
    cc1-32298 0 2 0 0 0 wakeup-0=2
    cc1-13743 0 18 0 0 0 wakeup-0=18
    cc1-22186 0 4 0 0 0 wakeup-0=4
    cc1-28214 0 11 0 0 0 wakeup-0=11
    cc1-13735 0 1 0 0 0 wakeup-0=1
    updatedb-8173 0 18 0 0 0 wakeup-0=18
    cc1-13750 0 3 0 0 0 wakeup-0=3
    cat-2808 0 2 0 0 0 wakeup-0=2
    cc1-15277 0 169 0 0 0 wakeup-0=169
    date-18317 0 1 0 0 0 wakeup-0=1
    cc1-15274 0 197 0 0 0 wakeup-0=197
    cc1-30732 0 1 0 0 0 wakeup-0=1

    Kswapd Kswapd Order Pages Pages Pages
    Instance Wakeups Re-wakeup Scanned Sync-IO ASync-IO
    kswapd0-311 91 24 357302 0 34233 wake-0=31 wake-1=1 wake-9=59 rewake-0=10 rewake-1=1 rewake-9=13

    Summary
    Direct reclaims: 291
    Direct reclaim pages scanned: 437794
    Direct reclaim write sync I/O: 6295
    Direct reclaim write async I/O: 46446
    Wake kswapd requests: 2152
    Time stalled direct reclaim: 519.163009000002 ms

    Kswapd wakeups: 91
    Kswapd pages scanned: 357302
    Kswapd reclaim write sync I/O: 0
    Kswapd reclaim write async I/O: 34233
    Time kswapd awake: 5282.749757 ms

    Signed-off-by: Mel Gorman
    Acked-by: Rik van Riel
    Acked-by: Larry Woodman
    Cc: Dave Chinner
    Cc: Chris Mason
    Cc: Nick Piggin
    Cc: Rik van Riel
    Cc: Johannes Weiner
    Cc: Christoph Hellwig
    Cc: KAMEZAWA Hiroyuki
    Cc: KOSAKI Motohiro
    Cc: Andrea Arcangeli
    Cc: Michael Rubin
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Mel Gorman