[LU-5608] Performance regression of removal operation with mdtest stride option

• Type: Bug
• Resolution: Incomplete
• Priority: Major
• Severity: 3
• Assignee: Lai Siyao
• Reporter: Wang Shilong (Inactive)

Description

While comparing Lustre 1.8 series with latest master release in client. Server is running the same 2.5 series. we found there is big file removal regression.

Testing command is:

1. mpirun -bind-to core:overload-allowed --map-by ppr:32:node --allow-run-as-root -np 512 -hostfile ./hostfile.32 ./mdtest -n 2000 -i 3 -p 10 -u -d /lustre_ {0-31}

   /mdtest.out -F -N 32

While comparing file removal performance between 1.8 and master is:
61476.175 op/seconds VS 39640.455 op/seconds.

Big regression, isn't it?

Notice here we need use '-N' option for mdtest, the problem seems only reproducible under multiple clients. Attachment is modified mdtest source codes which could help reproduce this problem.