[LU-15692] performance regressions for files in stripe directory

• Type: Bug
• Resolution: Fixed
• Priority: Blocker
• Fix Version/s: Lustre 2.15.0
• Affects Version/s: Lustre 2.15.0
• Severity: 3
• Assignee: Lai Siyao
• Reporter: Shuichi Ihara

Description

performance regressions in stripe directory on 2.15.0 (commit;4d93fd7) were found against b2_14(commit:d4b9557).
Here is configuration.

4 x MDS (1 x MDT per MDS)
4 x OSS (2 x OSS per OSS)
40 x client

[root@ec01 ~]# mkdir -p /exafs/d0/d1/d2/mdt_stripe/
[root@ec01 ~]# lfs setdirstripe -c 4 -D /exafs/d0/d1/d2/mdt_stripe/
[root@ec01 ~]# salloc -p 40n -N 40 --ntasks-per-node=16 mpirun --allow-run-as-root -oversubscribe -mca btl_openib_if_include mlx5_1:1 -x UCX_NET_DEVICES=mlx5_1:1 /work/tools/bin/mdtest -n 2000 -F -i 3 -p 10 -v -d /exafs/d0/d1/d2/mdt_stripe/

Here is test resutls.

server: version=2.15.0_RC2_22_g4d93fd7
client: version=2.15.0_RC2_22_g4d93fd7

SUMMARY rate: (of 3 iterations)
   Operation                     Max            Min           Mean        Std Dev
   ---------                     ---            ---           ----        -------
   File creation              103733.203      76276.410      93728.713      15168.101
   File stat                  693152.731     656461.448     671671.960      19132.425
   File read                  259081.462     247951.008     253393.168       5569.308
   File removal               145137.390     142142.699     143590.068       1499.846
   Tree creation                  48.035          1.922         17.475         26.467
   Tree removal                   35.643         15.861         24.045         10.323

server: version=2.14.0_21_gd4b9557
client: version=2.14.0_21_gd4b9557

SUMMARY rate: (of 3 iterations)
   Operation                     Max            Min           Mean        Std Dev
   ---------                     ---            ---           ----        -------
   File creation              138939.425      81336.388     117014.695      31167.261
   File stat                 1678888.952    1580356.340    1645190.276      56162.463
   File read                  569731.788     528830.155     546121.363      21170.387
   File removal               191837.291     186597.900     188595.661       2832.527
   Tree creation                 120.108          0.986         51.078         61.778
   Tree removal                   40.863         33.203         37.987          4.171

As far as I observed this, it seems to be server side regression since because performance with lustre-2.15 clients + lustre-2.14 was ok below.

server: version=2.14.0_21_gd4b9557
client: version=2.15.0_RC2_22_g4d93fd7

SUMMARY rate: (of 3 iterations)
   Operation                     Max            Min           Mean        Std Dev
   ---------                     ---            ---           ----        -------
   File creation              132009.360      74074.615     106514.108      29585.056
   File stat                 1570754.679    1457120.401    1532703.082      65457.038
   File read                  563710.286     540228.432     553871.772      12194.544
   File removal               189557.092     186065.253     187536.946       1809.374
   Tree creation                  54.678          1.883         19.576         30.399
   Tree removal                   42.065         41.677         41.875          0.194

I am running 'git bisect', can hopefully find an commit where started regression soon.

Issue Links

• is cloned by: LU-15720 imbalanced file creation in 'crush' striped directory
• is related to: LU-15479 sanity: test_316 failed lfs mv: /mnt/lustre/d316.sanity/d/file migrate failed: No such file or directory (2)
• is related to: LU-15502 mkdir returns -EBADF if default LMV is set in 2.12 client <-> 2.14 MDS system
• is related to: LU-15546 Shared Directory File Creates regression seen in 2.15 when comparing to 2.12.6
• is related to: LU-13481 sanity test_33h: MDT index mismatch 5 times
• is related to: LU-11025 DNE3: directory restripe
• is related to: LU-14459 DNE3: directory auto split during create