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  1. Lustre
  2. LU-13290

Write performance regression in ldiskfs patches

    Details

    • Type: Bug
    • Status: Resolved
    • Priority: Major
    • Resolution: Duplicate
    • Affects Version/s: None
    • Fix Version/s: None
    • Labels:
      None
    • Environment:
      CentOS7.7, master
    • Severity:
      3
    • Rank (Obsolete):
      9223372036854775807

      Description

      ldiskfs patch in master branch(commit 2c0b2b7) causes write performance regressions on large OST.
      There are two major performance regressions caused by "LU-12988 ldiskfs: mballoc to prefetch groups"" and "LU-12988 ldiskfs: skip non-loaded groups at cr=0/1".

      As I commented on LU-12988, patch https://review.whamcloud.com/#/c/37619 has odd behaviors on large OST.
      Howerver, even patch https://review.whamcloud.com/#/c/37619 reverts, there is still performance regression. After revert several ldiskfs patches, it seems that patch "LU-12988 ldiskfs: skip non-loaded groups at cr=0/1" causes another perforamnce regression.
      Here is test case and test resutls.

      8 clients (PPN=16), IOR (1MB, FPP) 
      $ salloc --nodes=8 --ntasks-per-node=16 mpirun --allow-run-as-root /work/tools/bin/ior -w -t 1m -b 1g -e -F -C -o /scratch/file
      
      cb86073 Revert "LU-12103 ldiskfs: don't search large block range if disk full"
      Max Write: 6890.87 MiB/sec (7225.60 MB/sec)
      
      19c4b48 Revert "LU-12988 ldiskfs: skip non-loaded groups at cr=0/1"
      Max Write: 6757.56 MiB/sec (7085.81 MB/sec)
      
      5222bf6 Revert "LU-13183 ldiskfs: Drop remove truncate warning patch"
      Max Write: 985.87 MiB/sec (1033.76 MB/sec)
      
      7b7c89c Revert "LU-12988 ldiskfs: mballoc to prefetch groups"
      Max Write: 991.18 MiB/sec (1039.33 MB/sec)
      
      2c0b2b7 LU-13166 osd-ldiskfs: fix to allow to get system inode
      Max Write: 2184.79 MiB/sec (2290.92 MB/sec)
      

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              • Assignee:
                wc-triage WC Triage
                Reporter:
                sihara Shuichi Ihara
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                Dates

                • Created:
                  Updated:
                  Resolved: