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diff --git a/chromium/docs/website/site/developers/profiling-flame-graphs/index.md b/chromium/docs/website/site/developers/profiling-flame-graphs/index.md new file mode 100644 index 00000000000..72398176f13 --- /dev/null +++ b/chromium/docs/website/site/developers/profiling-flame-graphs/index.md @@ -0,0 +1,56 @@ +--- +breadcrumbs: +- - /developers + - For Developers +page_name: profiling-flame-graphs +title: Profiling Blink using Flame Graphs +--- + +Quick how to explaining how to profile Blink tests on Linux and analyze the +results using flame graphs. + +<img alt="Example flame graph." +src="/developers/profiling-flame-graphs/flamegraph.png"> +[Interactive Example](https://blink.gs/images/line-layout-flame-graph.svg) + +## Prerequisites + +* perf - available in the package linux-tools on Ubuntu. +* FlameGraph - + [FlameGraph.zip](https://github.com/brendangregg/FlameGraph/archive/master.zip) + or see [github page](https://github.com/brendangregg/FlameGraph). + +## Instructions + +To get profiling data one needs to build chromium and/or content_shell with +`GYP_DEFINE+="profiling=1"` + +The basic strategy is to do the following: + +1. Build with `GYP_DEFINE+="profiling=1"` +2. Record using `perf record`. +3. Collapse stacks using `stackcollapse-perf.pl`. +4. Generate flame graph using `flamegraph.pl`. + +## Profiling a Performance Test + +For example, to profile and generate a visualization for the Blink +`Layout/line-layout.html` performance tests the following command sequence could +be used. This assumes that the FlameGraph software from above is in the `PATH`. + +GYP_DEFINES+="profiling=1" gclient runhooks ninja -C out/Release blink_tests +perf record -F 500 -g -q -- ./out/Release/content_shell \\ --dump-render-tree +\`pwd\`/third_party/WebKit/PerformanceTests/Layout/line-layout.html perf script +| stackcollapse-perf.pl | flamegraph.pl > /tmp/flamegraph.svg + +## Analyzing the Results + +The generated SVG file is an interactive document that can be opened in Chrome +(or any other browser). Clicking a stack frame will "zoom in" to that frame. See +the [Flame Graphs](http://www.brendangregg.com/flamegraphs.html) home page for +further information and other use cases. + +## Further Reading + +* [Chromium profiling on + linux](https://code.google.com/p/chromium/wiki/LinuxProfiling).
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