Re: [Intel-gfx] [PATCH v3 1/1] drm/i915/guc/slpc: Add selftest for slpc tile-tile interaction

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

On 10/30/2022 10:14 PM, 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
It actually passes if there was throttling. Only fails if actual 
frequency does not reach RP0 AND there was no throttle reasons.
>
> v2: Fix build error
> v3: Use IS_ERR_OR_NULL to check worker
>      Addressed cosmetic review comments (Tvrtko)
>
> Signed-off-by: Riana Tauro <riana.tauro@intel.com>
> ---
>   drivers/gpu/drm/i915/gt/selftest_slpc.c | 60 +++++++++++++++++++++++++
>   1 file changed, 60 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/gt/selftest_slpc.c b/drivers/gpu/drm/i915/gt/selftest_slpc.c
> index 82ec95a299f6..427e714b432b 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) {

So, for MTL, this will just stop the spinner from running on the media 
tile and return 0, right? Not sure we are testing anything in that case 
(just one spinner running on the Render tile). Should we try and find 
out what media RP0 is and expect that here?

Thanks,

Vinay.

> @@ -426,6 +435,56 @@ 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) {
> +		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;
> +		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 (IS_ERR_OR_NULL(threads[i].worker))
> +			continue;
> +
> +		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 +492,7 @@ 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;