Ancestors

Toot

Written by Christian Brauner 🦊🐺 on 2024-10-03 at 20:38

After searching for quite a while and no clear answer here's a question for the perf bubble. I have a multi-threaded test program and I want a kernel callgraph that shows me the overhead or percentage of each function in the callgraph (aggregated over all threads, I guess). The goal is to identify changes caused by various patches.

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Descendants

Written by Jens Axboe on 2024-10-03 at 20:43

@brauner Just use perf record -g -p and the recording will have all threads. perf report -g --no-children for displaying the profile with callgraph info.

Hmm?

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Written by Christian Brauner 🦊🐺 on 2024-10-03 at 20:47

@axboe I'll try that out and see what I get.

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Written by Stephen Brennan on 2024-10-03 at 20:54

@brauner

@axboe and to add onto that I'd recommend using the flame graph scripts, specifically difffolded.pl to compare two profiles and show increases/decreases in the call graph times.

https://www.brendangregg.com/blog/2014-11-09/differential-flame-graphs.html

https://github.com/brendangregg/FlameGraph

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