[LU-7801] Function level debug message filter

• Status: Closed
• Project: Lustre
• Type: Improvement
• Priority: Minor
• Reporter: Gu Zheng (Inactive)
• Assignee: Peter Jones
• Resolution: Won't Fix
• Labels: patch

Description

Debug messages are important to profiling, bug addressing and tuning, but tons of messages will be printed if we enabled debug on a running production system, especially heavy workload.
Though we have subsystem level message filter, and it is very useful if we just need to focus on specific subsystems, but the granularity is still too big if we want to only focus on some function, and the efficient messages are submerged in the messages ocean, though we can dump all the messages out and filter it in the user-space again and again.
If we have a native function level messages which make decision(print message or not) at the early print step, that means just print the message of specified functions, then we can make the debug messages only focus on what we want and ignore the uncorrelated ones. It will be very useful in the condition that we only want messages of specified functions.

Issue Links

• is related to: LU-8980 Add tracepoint support to Lustre

Comments

[Peter Jones]

Gu Zheng

This could indeed be useful. With discussions on the triage call today it sounds like it may be possible to leverage ftrace. We will be interested to hear what you find out

Peter

[Gerrit Updater]

Gu Zheng ([e-mail]) uploaded a new patch: http://review.whamcloud.com/18573
Subject: LU-7801 libcfs: add function level debug message filter
Project: fs/lustre-release
Branch: master
Current Patch Set: 1
Commit: 74c2e1560c07247466a2692c43a2a49b4d2956ce

[James A Simmons]

Gu Zheng I have started the work for tracepoint support. From my reading trace point has built in support for function filtering for trace events. I will need to explore more for this.

[Gu Zheng (Inactive)]

Hi James,

Pretty cool, looking forward to the new framework.
Yeah, trace point has native support to function filtering, and main idea of my patch is from it.

[James A Simmons]

After a discussion yesterday the scope of the tracepoint has been greatly reduced which means the filtering ideas hoped for under this ticket has been removed. So the current debug infrastructure is here to stay but during the discussion the topic was brought up about more fine grain filtering and it that idea was disliked so this feature will never be supported. I will close this ticket as Wouldn't fix since this is the case.