[LU-7140] Few 4 MB BRW rpcs from readahead path

• Status: Resolved
• Project: Lustre
• Type: Improvement
• Priority: Minor
• Reporter: Andrew Perepechko
• Assignee: WC Triage
• Resolution: Won't Fix
• Labels: patch

Description

We have found that setting osc.max_pages_per_rpc=1024 leads to few 4 MB BRW rpcs.

More details and a patch will be uploaded shortly.

Issue Links

• is related to: LU-7990 Large bulk IO support

Comments

[Gerrit Updater]

Andrew Perepechko ([e-mail]) uploaded a new patch: http://review.whamcloud.com/16374
Subject: LU-7140: configurable readahead step
Project: fs/lustre-release
Branch: master
Current Patch Set: 1
Commit: 500cc2eac76d1c24f807aa5faf4344a3372e5585

[James A Simmons]

I have to ask what is the advantage of making read ahead step size configurable? Wouldn't be simpler to just adjust the read ahead step to be based on max_pages_per_rpc instead. Also if their is a benefit to making the read ahead step configurable why in megabytes. I think it would be better in pages. Especially since user can pass in strange values that end up having to be rounded to the nearest page anyways.

[Andrew Perepechko]

James, since so many people requested to make the step automatic, I updated the patch according to Jinshan Xiong's proposal.

[Peter Jones]

I think that this work has been superceded by the developmentin LU-7990