Re: [Intel-gfx] [PATCH v4 1/1] drm/i915/guc/slpc: Add selftest for slpc tile-tile interaction

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

On 11/9/2022 3:25 AM, 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 checks if there is any throttling but does not fail
> if RP0 is not granted due to throttle reasons
>
> v2: Fix build error
> v3: Use IS_ERR_OR_NULL to check worker
>      Addressed cosmetic review comments (Tvrtko)
> v4: do not skip test on media engines if gt type is GT_MEDIA.
>      Use correct PERF_LIMIT_REASONS register for MTL (Vinay)

LGTM.

Reviewed-by: Vinay Belgaumkar <vinay.belgaumkar@intel.com>

>
> Signed-off-by: Riana Tauro <riana.tauro@intel.com>
> ---
>   drivers/gpu/drm/i915/gt/selftest_slpc.c | 70 +++++++++++++++++++++++--
>   1 file changed, 66 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gt/selftest_slpc.c b/drivers/gpu/drm/i915/gt/selftest_slpc.c
> index 82ec95a299f6..bd44ce73a504 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)
> @@ -212,7 +220,8 @@ static int max_granted_freq(struct intel_guc_slpc *slpc, struct intel_rps *rps,
>   	*max_act_freq =  intel_rps_read_actual_frequency(rps);
>   	if (*max_act_freq != slpc->rp0_freq) {
>   		/* Check if there was some throttling by pcode */
> -		perf_limit_reasons = intel_uncore_read(gt->uncore, GT0_PERF_LIMIT_REASONS);
> +		perf_limit_reasons = intel_uncore_read(gt->uncore,
> +						       intel_gt_perf_limit_reasons_reg(gt));
>   
>   		/* If not, this is an error */
>   		if (!(perf_limit_reasons & GT0_PERF_LIMIT_REASONS_MASK)) {
> @@ -310,9 +319,10 @@ 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) {
> +			if (gt->type != GT_MEDIA && (engine->class == VIDEO_DECODE_CLASS ||
> +						     engine->class == VIDEO_ENHANCEMENT_CLASS)) {
>   				igt_spinner_end(&spin);
>   				st_engine_heartbeat_enable(engine);
>   				err = 0;
> @@ -335,7 +345,8 @@ static int run_test(struct intel_gt *gt, int test_type)
>   			if (max_act_freq <= slpc->min_freq) {
>   				pr_err("Actual freq did not rise above min\n");
>   				pr_err("Perf Limit Reasons: 0x%x\n",
> -				       intel_uncore_read(gt->uncore, GT0_PERF_LIMIT_REASONS));
> +				       intel_uncore_read(gt->uncore,
> +							 intel_gt_perf_limit_reasons_reg(gt)));
>   				err = -EINVAL;
>   			}
>   		}
> @@ -426,6 +437,56 @@ 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 +494,7 @@ 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;