[Intel-gfx] [PATCH v2 1/1] drm/i915/guc/slpc: Add selftest for slpc tile-tile interaction

[Tauro, Riana]

On 10/28/2022 3:53 PM, Tvrtko Ursulin wrote:
> 
> Hi,
> 
> I peeked inside from curiosity and was pleasantly surprise to see 
> kthread_work is used! Some comments below.
> 
> On 28/10/2022 10:50, Riana Tauro wrote:
>> Run a workload on tiles simultaneously by requesting for RP0 frequency.
>> Pcode can however limit the frequency being granted due to throttling
>> reasons. This test fails if there is any throttling
>>
>> v2: Fix build error
>>
>> Signed-off-by: Riana Tauro <riana.tauro at intel.com>
>> ---
>>   drivers/gpu/drm/i915/gt/selftest_slpc.c | 63 +++++++++++++++++++++++++
>>   1 file changed, 63 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/i915/gt/selftest_slpc.c 
>> b/drivers/gpu/drm/i915/gt/selftest_slpc.c
>> index 82ec95a299f6..d19486772f5a 100644
>> --- a/drivers/gpu/drm/i915/gt/selftest_slpc.c
>> +++ b/drivers/gpu/drm/i915/gt/selftest_slpc.c
>> @@ -13,6 +13,14 @@ enum test_type {
>>       VARY_MAX,
>>       MAX_GRANTED,
>>       SLPC_POWER,
>> +    TILE_INTERACTION,
>> +};
>> +
>> +struct slpc_thread {
>> +    struct kthread_worker *worker;
>> +    struct kthread_work work;
>> +    struct intel_gt *gt;
>> +    int result;
>>   };
>>   static int slpc_set_min_freq(struct intel_guc_slpc *slpc, u32 freq)
>> @@ -310,6 +318,7 @@ static int run_test(struct intel_gt *gt, int 
>> test_type)
>>               break;
>>           case MAX_GRANTED:
>> +        case TILE_INTERACTION:
>>               /* Media engines have a different RP0 */
>>               if (engine->class == VIDEO_DECODE_CLASS ||
>>                   engine->class == VIDEO_ENHANCEMENT_CLASS) {
>> @@ -325,6 +334,7 @@ static int run_test(struct intel_gt *gt, int 
>> test_type)
>>           case SLPC_POWER:
>>               err = slpc_power(gt, engine);
>>               break;
>> +
> 
> Noise.
> 
>>           }
>>           if (test_type != SLPC_POWER) {
>> @@ -426,6 +436,58 @@ static int live_slpc_power(void *arg)
>>       return ret;
>>   }
>> +static void slpc_spinner_thread(struct kthread_work *work)
>> +{
>> +    struct slpc_thread *thread = container_of(work, typeof(*thread), 
>> work);
>> +
>> +    thread->result = run_test(thread->gt, TILE_INTERACTION);
>> +}
>> +
>> +static int live_slpc_tile_interaction(void *arg)
>> +{
>> +    struct drm_i915_private *i915 = arg;
>> +    struct intel_gt *gt;
>> +    struct slpc_thread *threads;
>> +    int i = 0, ret = 0;
>> +
>> +    threads = kcalloc(I915_MAX_GT, sizeof(*threads), GFP_KERNEL);
>> +    if (!threads)
>> +        return -ENOMEM;
>> +
>> +    for_each_gt(gt, i915, i) {
>> +        pr_info("Running on GT: %d\n", gt->info.id);
> 
> Not sure logging these makes sense since test runs on all tiles in 
> parallel anyway.
> 
>> +        threads[i].worker = kthread_create_worker(0, 
>> "igt/slpc_parallel:%d", gt->info.id);
>> +
>> +        if (IS_ERR(threads[i].worker)) {
>> +            ret = PTR_ERR(threads[i].worker);
>> +            break;
>> +        }
>> +
>> +        threads[i].gt = gt;
>> +        threads[i].result = 0;
> 
> No need to zero result due kcalloc and runs do not repeat.
> 
>> +        kthread_init_work(&threads[i].work, slpc_spinner_thread);
>> +        kthread_queue_work(threads[i].worker, &threads[i].work);
>> +    }
>> +
>> +    for_each_gt(gt, i915, i) {
>> +        int status;
>> +
>> +        if (!threads[i].worker)
>> +            continue;
> 
> Could be ERR_PTR by the look of it so it would crash below. Either gate 
> on threads[i].gt or use IS_ERR_OR_NULL.
> 
> Regards,
> 
> Tvrtko

Thank you Tvrtko for the review comments.
Will fix these.

Thanks
Riana

> 
>> +
>> +        kthread_flush_work(&threads[i].work);
>> +        status = READ_ONCE(threads[i].result);
>> +        if (status && !ret) {
>> +            pr_err("%s GT %d failed ", __func__, gt->info.id);
>> +            ret = status;
>> +        }
>> +        kthread_destroy_worker(threads[i].worker);
>> +    }
>> +
>> +    kfree(threads);
>> +    return ret;
>> +}
>> +
>>   int intel_slpc_live_selftests(struct drm_i915_private *i915)
>>   {
>>       static const struct i915_subtest tests[] = {
>> @@ -433,6 +495,7 @@ int intel_slpc_live_selftests(struct 
>> drm_i915_private *i915)
>>           SUBTEST(live_slpc_vary_min),
>>           SUBTEST(live_slpc_max_granted),
>>           SUBTEST(live_slpc_power),
>> +        SUBTEST(live_slpc_tile_interaction),
>>       };
>>       struct intel_gt *gt;