Re: [PATCH xenomai-images] ci: do not skip tests on vm that have been relaxed

On 7/7/26 13:21, Jan Kiszka wrote:
> On 03.07.26 16:00, Tobias Schaffner wrote:
>>
>>
>> On 7/3/26 14:07, Jan Kiszka wrote:
>>> On 03.07.26 13:54, Tobias Schaffner wrote:
>>>> Hi all,
>>>>
>>>> in some of my test runs the sched-tp-overrun test was failing with:
>>>> 2026-06-23T17:25:44 ../tests/sched-tp-overrun.c:119: FAILED:
>>>> evl_read_observable(tfd, &nf, 1) (=Resource temporarily unavailable)
>>>> 2026-06-23T17:25:44 ** sched-tp-overrun: BROKEN
>>>>
>>>> I only see this on virtual targets.
>>>> e.g.: https://code.siemens.com/ebsy/debian/xenomai-images/-/
>>>> jobs/393605372
>>>> Mostly on arm but also saw this on qemu-amd64 in one of my recent runs.
>>>>
>>>
>>> Maybe improper/missing synchronization during test startup? Or when is
>>> this hit?
>>
>>
>> Does not look like a synchronization problem to me.
>> The key part of the test failure is this combination:
>>
>> /*
>> * Trigger an overrun condition by staying busy for longer
>> * than the duration of our allotted time window.
>> */
>> for (;;) {
>>      evl_read_clock(EVL_CLOCK_MONOTONIC, &now);
>>      if (timespec_sub_ns(&now, &start) > OVERRUN_TIME)
>>          break;
>> }
>>
>> /*
>> * Now check whether we received the overrun event as
>> * expected. Since non-blocking input is enabled, a lack of
>> * notification would amount to an error (EAGAIN).
>> */
>> __Tcall_assert(ret, evl_read_observable(tfd, &nf, 1));
>>
>>
>> The OVERRUN_TIME of 200us seems to be not enough to trigger the overrun
>> or in some cases or at least the message was not send in time.
>>
>> I suspected the issue to be time stealing but saw the fixup parts of the
>> tp scheduler trying to handle missed time frames. I think we just have
>> to increase the overrun time but not sure how much to still keep the
>> fixup parts tested. I guess these code paths are only exercised on
>> virtual targets.
>>
> 
> So, do you want to drop tp-overrun from this patch for now, or how to
> proceed?

This is resolved now. The test is skipped since the merge of: 
84b8efc58b3db882d527e08b9e28af01fc5b2753 - "[PATCH libevl] tests: skip 
sched-tp-overrun in virtual environments"

Best,
Tobias

> Jan
>