[py-dev] Performance tests with py.test
holger at merlinux.eu
Mon Jun 4 11:10:55 CEST 2012
sorry for taking a while ...
On Thu, May 03, 2012 at 11:18 +1000, Bogdan Opanchuk wrote:
> For some reason this message has not shown up in the list archives, so
> I'll resend it again.
> On Sun, Apr 1, 2012 at 12:21 PM, holger krekel <holger at merlinux.eu> wrote:
> > do you want to consider performance regressions as a failure?
> Not really. I just need some table with performance results that I
> could get for different systems/versions and compare them. Besides,
> performance regressions can be implemented using existing
> functionality, because they do not have some continuous result
> associated with them — only pass/fail.
> > Could you maybe provide a simple example test file and make up
> > some example output that you'd like to see?
> Sure. Consider the following test file:
> import pytest
> def test_matrixmul():
> def test_reduce():
> # <some lengthy preparation that I do not want to time>
> # <actual work>
> return 1.0
> def test_fft():
> # <again, some lengthy preparation that I do not want to time>
> # <actual work>
> return 1.0, 1e10
> Here "test_matrixmul()" is a normal pass/fail test, "test_reduce()" is
> marked as performance test that returns execution time, and
> "test_fft()" is marked as a test that returns execution time + the
> number of operations (thus allowing us to calculate GFLOPS value).
> I have put together a clunky solution (see the end of this letter)
> using existing hooks that gives me more or less what I want to see:
> $ py.test -v
> test_test.py:3: test_matrixmul PASSED
> test_test.py:6: test_reduce 1.0 s
> test_test.py:10: test_fft 10.0 GFLOPS
> The only problem here is that I have to explicitly increase verbosity
> level. I'd prefer 'perf' marked tests show their result even for
> default verbosity, but I haven't found a way to do it yet.
not sure it helps but are you aware that you can put
addopts = -v
in a pytest.ini file?
> > Meanwhile, if you haven't already you might want to look at the output
> > of "py.test --durations=10" and see about its implementation (mostly
> > contained in _pytest/runner.py, grep for 'duration').
> Yes, I know about it, but it is not quite what I need:
> - it measures the time of the whole testcase, while I usually need to
> time only specific part
right. It differentiates between setup and runtest phases for a test, though.
> - it does not allow me to measure anything more complicated (e.g.
> GFLOPS, as another variant I may want to see the error value)
> - it prints its report after all the tests are finished, while it is
> much more convenient to see testcase result as soon as it is finished
> (my performance tests may run for quite a long time)
> So, the solution I have now is shown below. "pytest_pyfunc_call()"
> implementation annoys me the most, because I had to copy-paste it from
> python.py, so it exposes some py.test internals and can easily break
> when something (seemingly hidden) inside the library is changed.
That's true. If you want to open an issue about this (pytest_pyfunc_call
to return test function return value), i can see to care about it.
> def pytest_configure(config):
> config.pluginmanager.register(PerfPlugin(config), '_perf')
> class PerfPlugin(object):
> def __init__(self, config):
> def pytest_pyfunc_call(self, __multicall__, pyfuncitem):
> # collect testcase return result
> testfunction = pyfuncitem.obj
> if pyfuncitem._isyieldedfunction():
> res = testfunction(*pyfuncitem._args)
> funcargs = pyfuncitem.funcargs
> res = testfunction(**funcargs)
> pyfuncitem.result = res
> def pytest_report_teststatus(self, __multicall__, report):
> outcome, letter, msg = __multicall__.execute()
> # if we have some result attached to the testcase, print it
> instead of 'PASSED'
> if hasattr(report, 'result'):
> msg = report.result
> return outcome, letter, msg
> def pytest_runtest_makereport(self, __multicall__, item, call):
> report = __multicall__.execute()
> # if the testcase has passed, and has 'perf' marker, process its results
> if call.when == 'call' and report.passed and
> hasattr(item.function, 'perf'):
> perf = item.function.perf
> perftype = perf.args
> if perftype == 'seconds':
> report.result = str(item.result) + " s"
> seconds, operations = item.result
> report.result = str(operations / seconds / 1e9) + " GFLOPS"
> return report
We could also think about a convention that would allow setting
the short/longform (letter,msg) on the report object so that could
also get rid of the report_teststatus hook. I am slightly less
inclined to go for this because the above teststatus bit seems
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