Bug 203927

Summary: major speed regression due to c2fc2bc296f7
Product: Tools Reporter: Johannes Berg (johannes)
Component: Trace-cmd/KernelsharkAssignee: Default virtual assignee for Trace-cmd and kernelshark (tools_tracecmd_kernelshark)
Status: RESOLVED CODE_FIX    
Severity: normal CC: rostedt, tstoyanov
Priority: P1    
Hardware: All   
OS: Linux   
Kernel Version: n/a Subsystem:
Regression: Yes Bisected commit-id:

Description Johannes Berg 2019-06-18 17:53:49 UTC 
I have a ~1.7G file with just under 620k events (not exactly big by our standards), and parsing speed (with -N to disable plugins) goes from ~4.5 seconds on commit 1ad32c24746 to >>4.5 minutes (I aborted there) on master.

I was talking to Steven about another issue, and he pointed me to commit c2fc2bc296f7. Reverting that on master makes it take ~2 seconds, so that'd actually be an improvement.
Comment 1 Tzvetomir Stoyanov 2019-06-19 11:51:14 UTC 
Proposed solution: revert the behaviour for this use case, as it was before commit c2fc2bc296f7

https://patchwork.kernel.org/patch/11003953/
Comment 2 Steven Rostedt 2019-07-19 20:30:47 UTC 
Fixed by commit 0bdae7b3fbcd ("trace-cmd: Do not free pages from the lookup table in struct cpu_data in case trace file is loaded.").