Re: [PATCH 1/2] kselftests: timers: Make set-timer-lat fail more gracefully for !CAP_WAKE_ALARM

[Shuah Khan]

On 04/02/2015 11:17 AM, Tyler Baker wrote:
> On 2 April 2015 at 06:43, Shuah Khan <shuahkh@xxxxxxxxxxxxxxx> wrote:
>> On 04/02/2015 04:18 AM, Prarit Bhargava wrote:
>>>
>>>
>>> On 03/26/2015 01:33 PM, Tyler Baker wrote:
>>>> On 26 March 2015 at 09:29, John Stultz <john.stultz@xxxxxxxxxx> wrote:
>>>>> On Thu, Mar 26, 2015 at 4:31 AM, Prarit Bhargava <prarit@xxxxxxxxxx> wrote:
>>>>>> On 03/25/2015 07:44 PM, John Stultz wrote:
>>>>>>> +                     printf("%-22s %s missing CAP_WAKE_ALARM?    : [UNSUPPORTED]\n",
>>>>>>> +                                     clockstring(clock_id),
>>>>>>> +                                     flags ? "ABSTIME":"RELTIME");
>>>>>>
>>>>>> Something to think about:  Do you want to write these tests to be more human
>>>>>> readable or machine readable?  In theory with awk I guess it doesn't matter too
>>>>>> much, however, it is something that we should think about moving forward.
>>>>>
>>>>> So this came up at ELC in a few discussions. Right now there isn't any
>>>>> established output format, but there's some nice and simple
>>>>> infrastructure for counting pass/fails.
>>>>>
>>>>> However, in talking to Tyler, I know he has started looking at how to
>>>>> integrate the selftests into our automated infrastructure and was
>>>>> interested in how we improve the output parsing for reports. So there
>>>>> is interest in improving this, and I'm open to whatever changes might
>>>>> be needed (adding extra arguments to the test to put them into "easy
>>>>> parse" mode or whatever).
>>>>
>>>> Thanks for looping me in John. My interest in kselftest stems from my
>>>> involvement with kernelci.org, a communityservice focused on upstream
>>>> kernel validation across multiple architectures. In it's current form,
>>>> it is merely build and boot testing boards. However, we are at a point
>>>> where we'd like to start running some tests. The automation framework
>>>> (LAVA) used to execute these tests essentially uses a regular
>>>> expression to parse the test's standard output. This is advantageous
>>>> as a test can be written in any language, as long as it produces sane
>>>> uniform output.
>>>>
>>>> Ideally, we would like to perform the kernel builds as we do today
>>>> along with building all the kseltests present in the tree, and
>>>> inserting them into a 'testing' ramdisk for deployment. Once we
>>>> successfully boot the platform, we execute all the kselftests, parse
>>>> standard out, and report the results. The benefit from this
>>>> implementation is that a developer writing a test does have to do
>>>> anything 'special' to get his/her test to run once it has been applied
>>>> to a upstream tree. I'll explain below some concerns I have about
>>>> accomplishing this.
>>>>
>>>> Currently, we have had to write wrappers[1][2] for some kselftests to
>>>> be able parse the output. If we can choose/agree on a standard output
>>>> format all of this complexity goes away, and then we can dynamically
>>>> run kselftests. Integration of new tests will not be needed, as they
>>>> all produce output in standard way. I've taken a look at the wiki page
>>>> for standardizing output[3] and TAP looks like the good format IMO.
>>>>
>>>> Also, for arch != x86 there are some barriers to overcome to get all
>>>> the kselftests cross compiling, which would be nice to have as well.
>>>>
>>>> I realize this may be a good amount of work, so I'd like to help out.
>>>> Perhaps working John to convert his timer tests to use TAP output
>>>> would be a good starting point?
>>>
>>> John, I could probably do that for you.  I'm always willing to give it a shot.
>>>
>>
>> Improving reporting and output is a good idea, as long as the
>> reporting framework doesn't add external dependencies and makes
>> it difficult to build and run tests from the kernel git tree
>> environment. Being able to run tests on a development system
>> is the primary objective for these tests.
>>
>> As long as the TAP doesn't require additional libraries and
>> tools to be installed on the development systems, I will be
>> happy with the improvements to reporting and output.
> 
> This is a very valid concern IMO. There is a C library for TAP
> providers[0] but I agree we want to avoid external libraries as
> dependencies. Perhaps, it would be simple enough to write a selftest
> harness that provides a basic interface for displaying test results,
> messages, and warning/errors. This harness would ensure all the
> logging was done in a TAP compliant manner. Food for thought :)
> 

The harness has to cover tests in written in C as well as shell
scripts. I added a simple framework in kselftest.h as a step
towards harness. However, it needs more work. I would welcome
any patches that would provide a harness that meets the needs
of external selftest use-cases such as yours.

Is writing a simple TAP compliant harness something you can take
on?? Looking for volunteers :)

thanks,
-- Shuah

-- 
Shuah Khan
Sr. Linux Kernel Developer
Open Source Innovation Group
Samsung Research America (Silicon Valley)
shuahkh@xxxxxxxxxxxxxxx | (970) 217-8978
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