[Intel-gfx] [PATCH i-g-t 3/3] tests/gem_exec_schedule: Add test for resetting preemptive batch

[Antonio Argenziano]

On 04/12/17 09:42, Chris Wilson wrote:
> Quoting Antonio Argenziano (2017-12-04 17:23:15)
>> This patch adds a test that will trigger a preemption of a low priority
>> batch by a 'bad' batch buffer which will hang. The test aims at making
>> sure that a hanging high priority batch will not disrupt the submission
>> flow of low priority contexts.
>>
>> Cc: Chris Wilson <chris at chris-wilson.co.uk>
>> Cc: Michal Winiarski <michal.winiarski at intel.com>
>> Signed-off-by: Antonio Argenziano <antonio.argenziano at intel.com>
>> ---
>>   tests/gem_exec_schedule.c | 39 +++++++++++++++++++++++++++++++++++++++
>>   1 file changed, 39 insertions(+)
>>
>> diff --git a/tests/gem_exec_schedule.c b/tests/gem_exec_schedule.c
>> index ae44a6c0..5a4d63f9 100644
>> --- a/tests/gem_exec_schedule.c
>> +++ b/tests/gem_exec_schedule.c
>> @@ -511,6 +511,39 @@ static void preempt_self(int fd, unsigned ring)
>>          gem_close(fd, result);
>>   }
>>   
>> +static void bad_preemptive(int fd, unsigned ring)
>> +{
>> +       igt_spin_t *spin[16];
>> +       igt_spin_t *bad;
>> +       uint32_t ctx[2];
>> +
>> +       ctx[LO] = gem_context_create(fd);
>> +       gem_context_set_priority(fd, ctx[LO], MIN_PRIO);
>> +
>> +       ctx[HI] = gem_context_create(fd);
>> +       gem_context_set_priority(fd, ctx[HI], MAX_PRIO);
>> +
>> +       for (int n = 0; n < 16; n++) {
>> +               gem_context_destroy(fd, ctx[LO]);
>> +               ctx[LO] = gem_context_create(fd);
>> +               gem_context_set_priority(fd, ctx[LO], MIN_PRIO);
>> +
>> +               spin[n] = __igt_spin_batch_new(fd, ctx[LO], ring, 0, true);
>> +               igt_debug("spin[%d].handle=%d\n", n, spin[n]->handle);
>> +       }
>> +
>> +       bad = igt_spin_batch_new(fd, ctx[HI], ring, 0, false);
>> +       gem_wait(fd, bad->handle, NULL);
>> +
>> +       for (int n = 0; n < 16; n++) {
>> +               igt_assert(gem_bo_busy(fd, spin[n]->handle));
>> +               igt_spin_batch_free(fd, spin[n]);
>> +       }
> 
> Is this really policy you want to enforce? I certainly don't intend to
> mandate that the kernel isn't allowed to use RT throttling.

Yeah, I wasn't sure about that. Is a gem_wait on each of them enough or 
should I put a write at the end of each low priority batch to make sure 
they actually executed?

> 
>> +
>> +       gem_context_destroy(fd, ctx[LO]);
>> +       gem_context_destroy(fd, ctx[HI]);
>> +}
>> +
>>   static void deep(int fd, unsigned ring)
>>   {
>>   #define XS 8
>> @@ -1033,6 +1066,12 @@ igt_main
>>                                                  preempt(fd, e->exec_id | e->flags, NEW_CTX | HANG_LP);
>>                                                  igt_fork_hang_detector(fd);
>>                                          }
>> +
>> +                                       igt_subtest_f("bad-preemptive-%s", e->name) {
>> +                                               igt_stop_hang_detector();
>> +                                               bad_preemptive(fd, e->exec_id | e->flags);
>> +                                               igt_fork_hang_detector(fd);
>> +                                       }
> 
> Split into non-hang/hang portions and use igt_subtest_group +
> igt_fixture.

OK, will do.

-Antonio

> -Chris
>