[Piglit] Nearly finished: shader_runner running THOUSANDS of tests per process

Mark Janes mark.a.janes at intel.com
Fri May 27 13:10:37 UTC 2016

Marek Olšák <maraeo at gmail.com> writes:

> On Fri, May 27, 2016 at 3:18 AM, Mark Janes <mark.a.janes at intel.com> wrote:
>> Marek Olšák <maraeo at gmail.com> writes:
>>> On Mon, Apr 18, 2016 at 6:45 PM, Dylan Baker <baker.dylan.c at gmail.com> wrote:
>>>> Quoting Marek Olšák (2016-04-16 15:16:34)
>>>>> Hi,
>>>>> This makes shader_runner very fast. The expected result is 40%
>>>>> decrease in quick.py running time, or a 12x faster piglit run if you
>>>>> run shader tests alone.
>>>>> Branch:
>>>>> https://cgit.freedesktop.org/~mareko/piglit/log/?h=shader-runner
>>>>> Changes:
>>>>> 1) Any number of test files can be specified as command-line
>>>>> parameters. Those command lines can be insanely long.
>>>>> 2) shader_runner can re-create the window & GL context if test
>>>>> requirements demand different settings when going from one test to
>>>>> another.
>>>>> 3) all.py generates one shader_runner instance per group of tests
>>>>> (usually one or two directories - tests and generated_tests).
>>>>> Individual tests are reported as subtests.
>>>>> The shader_runner part is done. The python part needs more work.
>>>>> What's missing:
>>>>> Handling of crashes. If shader_runner crashes:
>>>>> - The crash is not shown in piglit results (other tests with subtests
>>>>> already have the same behavior)
>>>>> - The remaining tests will not be run.
>>>>> The ShaderTest python class has the list of all files and should be
>>>>> able to catch a crash, check how many test results have been written,
>>>>> and restart shader_runner with the remaining tests.
>>>>> shader_runner prints TEST %i: and then the subtest result. %i is the
>>>>> i-th file in the list. Python can parse that and re-run shader_runner
>>>>> with the first %i tests removed. (0..%i-1 -> parse subtest results; %i
>>>>> -> crash; %i+1.. -> run again)
>>>>> I'm by no means a python expert, so here's an alternative solution (for me):
>>>>> - Catch crash signals in shader_runner.
>>>>> - In the single handler, re-run shader_runner with the remaining tests.
>>>>> Opinions welcome,
>> Per-test process isolation is a key feature of Piglit that the Intel CI
>> relies upon.  If non-crash errors bleed into separate tests, results
>> will be unusable.
>> In fact, we wrap all other test suites in piglit primarily to provide
>> them with per-test process isolation.
>> For limiting test run-time, we shard tests into groups and run them on
>> parallel systems.  Currently this is only supported by dEQP features,
>> but it can make test time arbitrarily low if you have adequate hardware.
>> For test suites that don't support sharding, I think it would be useful
>> to generate suites from start/end times that can run the maximal set of
>> tests in the targeted duration.
>> I would be worried by complex handling of crashes.  It would be
>> preferable if separate suites were available to run with/without shader
>> runner process isolation.
>> Users desiring faster execution can spend the saved time figuring out
>> which test crashed.
> I would say that the majority of upstream users care more about piglit
> running time and less about process isolation.
> Process isolation can be an optional piglit flag.


>>>>> Marek
>>>>> _______________________________________________
>>>>> Piglit mailing list
>>>>> Piglit at lists.freedesktop.org
>>>>> https://lists.freedesktop.org/mailman/listinfo/piglit
>>>> Thanks for working on this Marek,
>>>> This has been discussed here several times amongst the intel group, and
>>>> the recurring problem to solve is crashing. I don't have a strong
>>>> opinion on python vs catching a fail in the signal handler, except that
>>>> handling in the python might be more robust, but I'm not really familiar
>>>> with what a C signal handler can recover from, so it may not.
>>> I can catch signals like exceptions and report 'crash'. Then I can
>>> open a new process from the handler to run the remaining tests, wait
>>> and exit.
>> Will an intermittent crash be run again until it passes?
> No.
> Marek

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