[LU-12535] lov_page_index surprisingly slow Created: 11/Jul/19 Updated: 24/Sep/19 Resolved: 16/Sep/19 |
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| Status: | Resolved |
| Project: | Lustre |
| Component/s: | None |
| Affects Version/s: | None |
| Fix Version/s: | Lustre 2.13.0 |
| Type: | Improvement | Priority: | Minor |
| Reporter: | Patrick Farrell (Inactive) | Assignee: | Patrick Farrell (Inactive) |
| Resolution: | Fixed | Votes: | 0 |
| Labels: | None | ||
| Issue Links: |
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| Rank (Obsolete): | 9223372036854775807 | ||||
| Description |
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When doing readahead, we see an amazing amount of time (~5%) just looking up the page index from the lov layer. a
- 84.42% 0.34% ior [kernel.kallsyms] [k] ll_readpage a
- 84.08% ll_readpage a
- 82.68% ll_io_read_page a
+ 68.53% ll_readahead.isra.27 a
- 14.14% cl_io_submit_rw a
- 13.40% lov_io_submit a
- 8.24% lov_page_index a
5.56% cl_page_at
This never changes once a page is created, so we can just store it at the top layer. |
| Comments |
| Comment by Gerrit Updater [ 11/Jul/19 ] |
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Patrick Farrell (pfarrell@whamcloud.com) uploaded a new patch: https://review.whamcloud.com/35470 |
| Comment by Patrick Farrell (Inactive) [ 11/Jul/19 ] |
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I thought this was due to a bug in another patch, but it seems to be, surprisingly, real. Let's get it fixed... |
| Comment by Gerrit Updater [ 16/Sep/19 ] |
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Oleg Drokin (green@whamcloud.com) merged in patch https://review.whamcloud.com/35470/ |
| Comment by Peter Jones [ 16/Sep/19 ] |
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Landed for 2.13 |