image-2023-06-06-00-23-09-738.png
ior_buffered.svg
ior_odirect.svg
[LU-16875] spinlock contention at pagecache during buffered ior test Created: 05/Jun/23 Updated: 05/Jun/23 |
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| Status: | Open |
| Project: | Lustre |
| Component/s: | None |
| Affects Version/s: | Lustre 2.15.2 |
| Fix Version/s: | None |
| Type: | Bug | Priority: | Minor |
| Reporter: | Sergey Kachkin | Assignee: | WC Triage |
| Resolution: | Unresolved | Votes: | 0 |
| Labels: | None | ||
| Environment: |
Rocky linux 8.7-ib, Lustre 15.2.2, 1 OSS / 4 OST , single client |
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| Attachments: |
image-2023-06-06-00-23-09-738.png
ior_buffered.svg
ior_odirect.svg
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| Epic/Theme: | Performance |
| Severity: | 3 |
| Rank (Obsolete): | 9223372036854775807 |
| Description |
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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. |
