[LU-14917] allow switching mmap readahead logic Created: 06/Aug/21  Updated: 24/Nov/23

Status: Open
Project: Lustre
Component/s: None
Affects Version/s: None
Fix Version/s: Lustre 2.16.0

Type: Improvement Priority: Minor
Reporter: Patrick Farrell Assignee: Patrick Farrell
Resolution: Unresolved Votes: 0
Labels: readahead

Issue Links:
Related
is related to LU-14921 sanity test_101f test_101k: mmap miss... Open
is related to LU-15100 Add ability to tune definition of loo... Open
Rank (Obsolete): 9223372036854775807

 Description   

We have seen some customer workloads doing mmap where the mmap readahead algorithm works very poorly.  Investigation showed that the workload is much more like a traditional sequential workload.  Changing the mmap readahead tunables and using madvise both did not result in good readahead behavior.

Instead, we tried allowing mmap readahead to use the standard readahead logic, rather than the mmap specific logic.  This worked really well for this workload, so I'm pushing a patch to make that a tunable.



 Comments   
Comment by Gerrit Updater [ 06/Aug/21 ]

Patrick Farrell (pfarrell@whamcloud.com) uploaded a new patch: https://review.whamcloud.com/44526
Subject: LU-14917 llite: Switch mmap readahead logic
Project: fs/lustre-release
Branch: master
Current Patch Set: 1
Commit: e84c44f1e79e4bc5c333e760930158b1470600e9

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