Jordan Delong
363d1bb20f
This change is mostly for FB internal organizational reasons. Building is not effected beyond the fact that the target now lands in hphp/hhvm/hhvm rather than src/hhvm/hhvm.
56 linhas
1.7 KiB
Plaintext
56 linhas
1.7 KiB
Plaintext
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<h2>Using Google CPU Profiler</h2>
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Building with GOOGLE_CPU_PROFILER set lets you collect profiles from
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the server or from the command line. However, our testing has found
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that the server can get stalled while profiling for reasons
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unknown. Still, it's possible to get enough requests in that the
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profile can be significant.
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There are two stages in profiling, collecting the profile and
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processing it into a readable format. Collection is different on the
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command line and server.
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= Profiling from the command line
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For building stand alone programs you need to link with libprofiler and
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libunwind:
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export LIBRARY_PATH=[path]/hphp/external/google-perftools/lib:\
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[path]/hphp/external/libunwind/lib
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g++ <my program>.cpp -lprofiler
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With a compiled program, p, execute:
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CPUPROFILE=p.prof CPUPROFILE_FREQUENCY=1000 p args
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This will create a file p.prof when p finishes while taking samples 1000
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times per second. The frequency can be changed: higher frequencies
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will impact performance but lower frequencies will require a longer
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run to collect a significant number of samples.
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= Profiling from the server
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Run
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GET http://[server]:8088/prof-cpu-on
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Then hit the server some number of times. When satisfied,
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GET http://[server]:8088/prof-cpu-off
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A file /hphp/pprof/[host]/hphp.prof should be created. The exact path is
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configurable with the runtime option Debug.ProfilerOutputDir
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(defaults to /tmp on production).
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= Processing the profile
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Use the tool pprof to process the profile. For example:
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pprof --gif p p.prof > p.gif
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This generates a gif with the callgraph of p.
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Note that if you needed to strip the program, it's still possible
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to use pprof if you call it on the unstripped version.
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