What Are Flame Graphs and How to Read Them - RubyConfBY 2017

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! @mr_foto

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" @mr_foto

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HOW YOU REMEMBER SLOVENIA

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HOW I REMEMBER BELARUS

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@mr_foto Software Developer Team Lead Git Blame Navigator Time Zone Resolver

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@mr_foto Software Developer Team Lead Git Blame Navigator Time Zone Resolver Slack Emoji Creator

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$FLAME GRAPHS$

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WHY AND WHAT Interactive visualization of stack traces From beginners to experts How SW is consuming CPU Brendan Gregg

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SAMPLING My Day Reading Emails

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My Day Reading Emails Replying to Emails SAMPLING

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My Day Writing Code SAMPLING

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My Day Writing Code Writing Tests SAMPLING

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My Day Writing Code Writing Tests Running Tests SAMPLING

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My Day Writing Code Writing Tests Running Tests Fixing Tests SAMPLING

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My Day Writing Code Running Tests SAMPLING

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My Day Making Espresso SAMPLING

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SAMPLING My Day Reading Emails

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My Day Writing Code SAMPLING

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My Day Writing Code Running Tests SAMPLING

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My Day Reading Emails Replying to Emails SAMPLING

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GROUPING

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GROUPING

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GROUPING My Day Reading Emails Replying Writing Code ☕ Writing Tests Running Running Fix

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FLAME GRAPH Function

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FLAME GRAPH Function

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FLAME GRAPH Function

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FLAME GRAPH Stack Depth

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FLAME GRAPH Stack Depth

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FLAME GRAPH Stack Depth

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FLAME GRAPH Stack Depth

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FLAME GRAPH Ordered by Alphabet

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FLAME GRAPH Ordered by Alphabet

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FLAME GRAPH Total Time on CPU

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FLAME GRAPH Total Time on CPU

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FLAME GRAPH Total Time on CPU

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WHO WANTS A T-SHIRT?

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Q&A Q: Which function is on CPU the most?

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Q&A A: f() top edge shows what is on CPU directly

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Q&A Q: Why is f() on CPU?

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Q&A A: a() → b() → c() → e() → f() f() was called by e(), e() was called by c(),…

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Q&A Q: How does b() compare to g()?

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Q&A A: b() looks like it is running (present) about 10 times more often than g()

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USING WITH RUBY Sam Saﬀron gem 'ﬂamegraph' Flamegraph.generate(filename) do # your work here end

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TOPTAL.BLOG

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ORIGINAL 1.083 (± 0.0%) i/s - 33.000 in 30.86s

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CACHE KRAMDOWN 8.368 (±12.0%) i/s - 244.000 in 30.04s

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CACHE KRAMDOWN 8.368 (±12.0%) i/s - 244.000 in 30.04s 7.5x improvement

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MEMOIZATION & CO. 10.140(± 9.9%) i/s - 292.000 in 30.03s

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MEMOIZATION & CO. 10.140(± 9.9%) i/s - 292.000 in 30.03s 9.4x improvement

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NOW WHAT? You’re here Ask me Ask someone smarter than me Ask anyone else Read/watch blog posts/videos