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@@ -173,25 +173,25 @@ Here are some basic instructions
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* `opcontrol --dump;`
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* `opreport -l that_dir/*`
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- Profit
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Profiling Tor with perf
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This works with a running Tor, and requires root.
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1. Decide how long you want to profile for. Start with (say) 30 seconds. If that
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works, try again with longer times.
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2. Find the PID of your running tor process.
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3. Run `perf record --call-graph dwarf -p <PID> sleep <SECONDS>`
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(You may need to do this as root.)
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You might need to add `-e cpu-clock` as an option to the perf record line
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above, if you are on an older CPU without access to hardware profiling
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events, or in a VM, or something.
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4. Now you have a perf.data file. Have a look at it with `perf report
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--no-children --sort symbol,dso` or `perf report --no-children --sort
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symbol,dso --stdio --header`. How does it look?
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@@ -220,7 +220,7 @@ performance! See the gperftools manual for more info, but basically:
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2. Run `env CPUPROFILE=/tmp/profile src/or/tor -f <path/torrc>`. The profile file
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is not written to until Tor finishes execuction.
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3. Run `pprof src/or/tor /tm/profile` to start the REPL.
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Generating and analyzing a callgraph
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Nick Mathewson