Saving 13M Computational Minutes per Day with Flame Graphs

Re:Saving 13M Computational Minutes per Day with Flame Graphs by alexc05 on Monday April 11, 2016 @03:17PM (#11474335)

I saw a youtube talk on this one ... I think it was this one: https://www.youtube.com/watch?v=O1YP8QP9gLA

Really great stuff. The spot where he gets to a pretty good description of how he uses his flame graph is roughly here: https://youtu.be/O1YP8QP9gLA?t=611

With respect to that blog-post the bit about the truncated towers is a bit of a red herring if you're 100% new to flame graphs.

The real meaty bits are the wide sections.

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Re:Saving 13M Computational Minutes per Day with Flame Graphs by MikeTheJoker on Monday April 11, 2016 @03:39PM (#11474498)

Generally you're right that the wide sections are where you want to focus your attention when looking for optimizations. The point I was trying to make in the blog post is that we had to take the flame graph visualization a step further to eliminate the noise obscuring a major hot spot. The large number of broken stacks was one of the first hurdles we had to cross to improve the clarity of the visualization.

BTW, this is a different flame graph and optimization than the one discussed in the YouTube video. We use flame graphs extensively throughout Netflix.

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Re:Saving 13M Computational Minutes per Day with Flame Graphs by m4dc4pXXX on Monday April 11, 2016 @04:43PM (#11474929)

Can you write up how you fixed the broken call stacks? I've used Brendan's tools (with java-perf-map, also an awesome tool) to generate flame graphs for Scala code and had no idea I could only see 127 frames.

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Re:Saving 13M Computational Minutes per Day with Flame Graphs by brendangregg on Monday April 11, 2016 @04:49PM (#11474965)

We ultimately should be fixing this with BPF, which we'll certainly post instructions for.

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