Uploaded image for project: 'Lustre'
  1. Lustre
  2. LU-1158 nanosecond timestamp support for Lustre
  3. LU-1619

Subtle and infrequent failure of test 39a in sanityn.sh noticed after ns timestamp implementation

    XMLWordPrintable

    Details

    • Type: Technical task
    • Status: Resolved
    • Priority: Minor
    • Resolution: Duplicate
    • Affects Version/s: Lustre 2.3.0
    • Fix Version/s: None
    • Labels:
    • Environment:
      CentOS 6.2/x86_64 on Maloo
    • Story Points:
      3
    • Rank (Obsolete):
      10374

      Description

      The results of a Maloo automated test of the nanosecond timestamp patches (LU-1158, http://review.whamcloud.com/#change,3266 and http://review.whamcloud.com/#change,3271, the latter of which includes a revised sanityn.sh for testing nanosecond times) revealed a slight time desynchronization after file renaming in test 39a of the revised sanityn.sh, on the order of 500,000 nanoseconds (about 1/2 of a millisecond) or so. This failure occurred 1 time out of 100 trials. Since the previous maximum time granularity of Lustre was at second resolution, and this bug cropped up 1% of the time during testing, it is highly unlikely that this bug would be noticed or reproducible without application of the LU-1158 patches; for it to be noticed, of the 1% of times the bug occurs, the 1/2 millisecond difference would have to occur across a second boundary, i.e. the second timestamps would have to be different. However, since the patches do not change any logic outside of determining when a timestamp is greater than another, it is possible that this bug exists undetected in master.

      Links to related Maloo test session and sanityn.sh failure:
      https://maloo.whamcloud.com/test_sessions/fd767d96-ca51-11e1-a9ff-52540035b04c
      https://maloo.whamcloud.com/test_sets/34a6a812-ca53-11e1-a9ff-52540035b04c

        Attachments

          Issue Links

            Activity

              People

              Assignee:
              wc-triage WC Triage
              Reporter:
              adilger Andreas Dilger
              Votes:
              0 Vote for this issue
              Watchers:
              0 Start watching this issue

                Dates

                Created:
                Updated:
                Resolved: