[LU-16875] spinlock contention at pagecache during buffered ior test

Mon, 5 Jun 2023 21:29:06 +0000

Lustre is configured with small configuration 1 OSS /4 OST

During single threaded buffered test with IOR I noticed high system CPU usage and spinlock contention at between IOR and ptlrpcd.

buffered ior executed like below:

ior -F -w -b 64g -t 256m -e -o /lustre/

This seems expected that during the buffered test there is high pressure on pagecache but I wonder if this spinlock contention between IOR and ptlrpcd can be somehow avoided.

Additionally I did direct IO test and as expected I do not see any lock contention but

direct io test:

ior -b 64g -t 256m -e -w -r -o /lustre/iorfile --posix.odirect

During direct IO test there is no contention (as expected) but IOR still consumes a lot of CPU time due to memory operations.

Whamcloud Community JIRA

[LU-16875] spinlock contention at pagecache during buffered ior test