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vmprof - a statistical program profiler
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VMProf Python package

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Head over to for more info!


pip install vmprof
python -m vmprof <your program> <your program args>

Our build system ships wheels to PyPI (Linux, Mac OS X). If you build from source you need to install CPython development headers and libunwind headers (on Linux only). On Windows this means you need Microsoft Visual C++ Compiler for your Python version.


Setting up development can be done using the following commands:

$ virtualenv -p /usr/bin/python3 vmprof3
$ source vmprof3/bin/activate
$ python develop

You need to install python development packages. In case of e.g. Debian or Ubuntu the package you need is python3-dev and libunwind-dev. Now it is time to write a test and implement your feature. If you want your changes to affect, head over to and follow the setup instructions.

Consult our section for development at for more information.


vmprofshow is a command line tool that comes with VMProf. It can read profile files and produce a formatted output.

Here is an example of how to use vmprofshow:

Run that smallish program which burns CPU cycles (with vmprof enabled):

pypy vmprof/test/ # you can find in the vmprof-python repo

This will produce a profile file vmprof_cpuburn.dat. Now display the profile:

vmprofshow vmprof_cpuburn.dat

You will see a (colored) output:

oberstet@thinkpad-t430s:~/scm/vmprof-python$ vmprofshow vmprof_cpuburn.dat
100.0%  <module>  100.0%  tests/
100.0% .. test  100.0%  tests/
100.0% .... burn  100.0%  tests/
 99.2% ...... _iterate  99.2%  tests/
 97.7% ........ _iterate  98.5%  tests/
 22.9% .......... _next_rand  23.5%  tests/
 22.9% ............ JIT code  100.0%  0x7fa7dba57a10
 74.7% .......... JIT code  76.4%  0x7fa7dba57a10
  0.1% .......... JIT code  0.1%  0x7fa7dba583b0
  0.5% ........ _next_rand  0.5%  tests/
  0.0% ........ JIT code  0.0%  0x7fa7dba583b0

Line profiling

vmprof supports line profiling mode, which enables collecting and showing the statistics for separate lines inside functions.

To enable collection of lines statistics add --lines argument to vmprof:

python -m vmprof --lines -o <output-file> <your program> <your program args>

Or pass lines=True argument to vmprof.enable function, when calling vmprof from code.

To see line statistics for all functions add the --lines argument to vmprofshow:

vmprofshow --lines <output-file>

To see line statistics for a specific function use the --filter argument with the function name:

vmprofshow --lines --filter <function-name> <output-file>

You will see the result:

macbook-pro-4:vmprof-python traff$ vmprofshow --lines --filter _next_rand vmprof_cpuburn.dat
Total hits: 1170 s
File: tests/
Function: _next_rand at line 14

Line #     Hits   % Hits  Line Contents
    14       38      3.2      def _next_rand(self):
    15                            #
    16      835     71.4          self._rand = (1103515245 * self._rand + 12345) & 0x7fffffff
    17      297     25.4          return self._rand
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