[igt-dev] [PATCH i-g-t] i915/perf_pmu: Exercise mixing perf reads into i915 mmaps

[Tvrtko Ursulin]

On 02/04/2020 15:07, Chris Wilson wrote:
> Quoting Chris Wilson (2020-04-02 15:00:57)
>> Feed a fresh i915 mmap into a read(perf_fd) to teach lockdep about the
>> potential lock chains should we take a pagefault into our vm_fault
>> handlers from within perf.
>>
>> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
>> Cc: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
>> ---
>>   tests/perf_pmu.c | 39 +++++++++++++++++++++++++++++++++++++++
>>   1 file changed, 39 insertions(+)
>>
>> diff --git a/tests/perf_pmu.c b/tests/perf_pmu.c
>> index 259670f4b..1d6681d80 100644
>> --- a/tests/perf_pmu.c
>> +++ b/tests/perf_pmu.c
>> @@ -1827,6 +1827,35 @@ accuracy(int gem_fd, const struct intel_execution_engine2 *e,
>>          assert_within(100.0 * busy_r, 100.0 * expected, 2);
>>   }
>>   
>> +static void *create_mmap(int gem_fd, const struct mmap_offset *t, int sz)
>> +{
>> +       uint32_t handle;
>> +       void *ptr;
>> +
>> +       handle = gem_create(gem_fd, sz);
>> +       ptr = __gem_mmap_offset(gem_fd, handle, 0, sz, PROT_WRITE, t->type);
>> +       gem_close(gem_fd, handle);
>> +
>> +       return ptr;
>> +}
>> +
>> +static void
>> +faulting_read(int gem_fd, const struct mmap_offset *t)
>> +{
>> +       void *ptr;
>> +       int fd;
>> +
>> +       ptr = create_mmap(gem_fd, t, 4096);
>> +       igt_require(ptr != NULL);
>> +
>> +       fd = open_pmu(gem_fd, I915_PMU_ENGINE_BUSY(0, 0));
>> +       igt_require(fd != -1);
>> +       igt_assert_eq(read(fd, ptr, 4096), 2 * sizeof(uint64_t));
>> +       close(fd);
>> +
>> +       munmap(ptr, 4096);
>> +}
>> +
>>   #define test_each_engine(T, i915, e) \
>>          igt_subtest_with_dynamic(T) __for_each_physical_engine(i915, e) \
>>                  igt_dynamic_f("%s", e->name)
>> @@ -1860,6 +1889,16 @@ igt_main
>>          igt_subtest("invalid-init")
>>                  invalid_init(fd);
>>   
>> +       igt_subtest_with_dynamic("faulting-read") {
>> +               for_each_mmap_offset_type(fd, t) {
>> +                       if (!gem_has_mmap_offset_type(fd, t))
>> +                               continue;
> 
> Redundant, for_each_mmap_offset_type() includes the skip.

Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>

Regards,

Tvrtko