Re: [PATCH i-g-t 2/2] tests/xe_pmu: Add frequency test

["Belgaumkar, Vinay" <vinay.belgaumkar@intel.com>]

On 4/9/2025 2:58 AM, Riana Tauro wrote:
> Hi Vinay
>
> On 4/8/2025 5:14 AM, Vinay Belgaumkar wrote:
>> Add a basic test that uses PMU to read GT actual and requested
>> frequencies while running a workload.
>>
>> v2: Rebase and comments (Riana)
>>
>> Cc: Lucas De Marchi <lucas.demarchi@intel.com>
>> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
>> Cc: Riana Tauro <riana.tauro@intel.com>
>> Signed-off-by: Vinay Belgaumkar <vinay.belgaumkar@intel.com>
>> ---
>>   tests/intel/xe_pmu.c | 128 ++++++++++++++++++++++++++++++++++++++++++-
>>   1 file changed, 127 insertions(+), 1 deletion(-)
>>
>> diff --git a/tests/intel/xe_pmu.c b/tests/intel/xe_pmu.c
>> index 175bbf374..fbac9c798 100644
>> --- a/tests/intel/xe_pmu.c
>> +++ b/tests/intel/xe_pmu.c
>> @@ -376,6 +376,94 @@ static void test_gt_c6_idle(int xe, unsigned int 
>> gt)
>>       close(pmu_fd);
>>   }
>>   +/**
>> + * SUBTEST: gt-frequency
>> + * Description: Validate we can collect accurate frequency PMU stats
>> + *        while running a workload.
>> + */
>> +static void test_gt_frequency(int fd, struct 
>> drm_xe_engine_class_instance *eci)
>> +{
>> +    struct xe_cork *cork = NULL;
>> +    uint64_t end[2], start[2];
>> +    unsigned long config_rq_freq, config_act_freq;
>> +    double min[2], max[2];
>> +    uint32_t gt = eci->gt_id;
>> +    uint32_t orig_min = xe_gt_get_freq(fd, eci->gt_id, "min");
>> +    uint32_t orig_max = xe_gt_get_freq(fd, eci->gt_id, "max");
>> +    uint32_t vm;
>> +    int pmu_fd[2];
>> +
>> +    config_rq_freq = get_event_config(gt, NULL, 
>> "gt-requested-frequency");
>> +    pmu_fd[0] = open_group(fd, config_rq_freq, -1);
>> +
>> +    config_act_freq = get_event_config(gt, NULL, 
>> "gt-actual-frequency");
>> +    pmu_fd[1] = open_group(fd, config_act_freq, pmu_fd[0]);
>> +
>> +    vm = xe_vm_create(fd, 0, 0);
>> +
>> +    cork = xe_cork_create_opts(fd, eci, vm, 1, 1);
>> +    xe_cork_sync_start(fd, cork);
>> +
>> +    /*
>> +     * Set GPU to min frequency and read PMU counters.
>> +     */
>> +    igt_assert(xe_gt_set_freq(fd, gt, "max", orig_min) > 0);
>> +    igt_assert(xe_gt_get_freq(fd, gt, "max") == orig_min);
>> +
>> +    pmu_read_multi(pmu_fd[0], 2, start);
>> +    usleep(SLEEP_DURATION * USEC_PER_SEC);
>> +    pmu_read_multi(pmu_fd[0], 2, end);
>> +
>> +    min[0] = (end[0] - start[0]);
>> +    min[1] = (end[1] - start[1]);
>> +
>> +    /*
>> +     * Set GPU to max frequency and read PMU counters.
>> +     */
>> +    igt_assert(xe_gt_set_freq(fd, gt, "max", orig_max) > 0);
>> +    igt_assert(xe_gt_get_freq(fd, gt, "max") == orig_max);
>> +    igt_assert(xe_gt_set_freq(fd, gt, "min", orig_max) > 0);
>> +    igt_assert(xe_gt_get_freq(fd, gt, "min") == orig_max);
>> +
>> +    pmu_read_multi(pmu_fd[0], 2, start);
>> +    usleep(SLEEP_DURATION * USEC_PER_SEC);
>> +    pmu_read_multi(pmu_fd[0], 2, end);
>> +
>> +    max[0] = (end[0] - start[0]);
>> +    max[1] = (end[1] - start[1]);
>> +
>> +    xe_cork_sync_end(fd, cork);
>> +
>> +    /*
>> +     * Restore min/max.
>> +     */
>> +    igt_assert(xe_gt_set_freq(fd, gt, "min", orig_min) > 0);
>> +    igt_assert(xe_gt_get_freq(fd, gt, "min") == orig_min);
>> +
>> +    igt_info("Minimum frequency: requested %.1f, actual %.1f\n",
>> +         min[0], min[1]);
>> +    igt_info("Maximum frequency: requested %.1f, actual %.1f\n",
>> +         max[0], max[1]);
>> +
>> +    close(pmu_fd[0]);
>> +    close(pmu_fd[1]);
>> +
>> +    if (cork)
>> +        xe_cork_destroy(fd, cork);
>> +
>> +    xe_vm_destroy(fd, vm);
>> +
>> +    close(pmu_fd[0]);
>> +    close(pmu_fd[1]);
>> +
>> +    assert_within_epsilon(min[0], orig_min, tolerance);
>> +    /*
>> +     * On thermally throttled devices we cannot be sure maximum 
>> frequency
>> +     * can be reached so use larger tolerance downwards.
>> +     */
>> +    assert_within_epsilon_up_down(max[0], orig_max, tolerance, 0.15f);
>> +}
>> +
>>   static unsigned int enable_and_provision_vfs(int fd)
>>   {
>>       unsigned int gt, num_vfs;
>> @@ -429,8 +517,9 @@ static void disable_vfs(int fd)
>>     igt_main
>>   {
>> -    int fd, gt;
>> +    int fd, gt, num_gts;
>>       struct drm_xe_engine_class_instance *eci;
>> +    uint32_t *stash_min, *stash_max;
>>         igt_fixture {
>>           fd = drm_open_driver(DRIVER_XE);
>> @@ -482,6 +571,43 @@ igt_main
>>               disable_vfs(fd);
>>       }
>>   +    igt_subtest_group {
>> +        igt_fixture {
>> +            igt_require(xe_sysfs_gt_has_node(fd, 0, "freq0"));
>> +            num_gts = xe_number_gt(fd);
>> +
>> +            stash_min = (uint32_t *) malloc(sizeof(uint32_t) * 
>> num_gts);
>> +            stash_max = (uint32_t *) malloc(sizeof(uint32_t) * 
>> num_gts);
>> +
>> +            xe_for_each_gt(fd, gt) {
>> +                stash_min[gt] = xe_gt_get_freq(fd, gt, "min");
>> +                stash_max[gt] = xe_gt_get_freq(fd, gt, "max");
> This can be moved inside the igt_subtest with local variables since 
> it's only one test. The subtest group is executed for all the other 
> tests too

ok.

Thanks,

Vinay.

>
> Thanks
> Riana> +            }
>> +        }
>> +
>> +        igt_describe("Validate PMU GT freq measured is within the 
>> tolerance");
>> +        igt_subtest_with_dynamic("gt-frequency") {
>> +            xe_for_each_gt(fd, gt) {
>> +                igt_dynamic_f("gt%u", gt)
>> +                xe_for_each_engine(fd, eci) {
>> +                    if (gt == eci->gt_id) {
>> +                        test_gt_frequency(fd, eci);
>> +                        break;
>> +                    }
>> +                }
>> +            }
>> +        }
>> +
>> +        igt_fixture {
>> +            xe_for_each_gt(fd, gt) {
>> +                xe_gt_set_freq(fd, gt, "max", stash_max[gt]);
>> +                xe_gt_set_freq(fd, gt, "min", stash_min[gt]);
>> +            }
>> +            free(stash_min);
>> +            free(stash_max);
>> +        }
>> +    }
>> +
>>       igt_fixture {
>>           close(fd);
>>       }
>