[igt-dev] [PATCH i-g-t 6/7] i915/gem_scheduler: Make gem_scheduler understand static priority mapping

[Daniele Ceraolo Spurio]

On 7/27/2021 8:22 AM, Matthew Brost wrote:
> The i915 currently has 2k visible priority levels which are currently
> unique. This is changing to statically map these 2k levels into 3
> buckets:
>
> low: < 0
> mid: 0
> high: > 0
>
> Update gem_scheduler to understand this. This entails updating promotion
> test to use 3 levels that will map into different buckets and also
> delete a racey check. Also skip any tests that rely on having more than

Can you elaborate on why the check is racey? I'm sure you've already 
explained it to me in the past but can't spot it right now.

> 3 priority levels.
>
> Signed-off-by: Matthew Brost <matthew.brost at intel.com>
> ---
>   lib/i915/gem_scheduler.c       | 13 ++++++++++
>   lib/i915/gem_scheduler.h       |  1 +
>   tests/i915/gem_exec_schedule.c | 47 ++++++++++++++++++++--------------
>   3 files changed, 42 insertions(+), 19 deletions(-)
>
> diff --git a/lib/i915/gem_scheduler.c b/lib/i915/gem_scheduler.c
> index cdddf42ad..bec2e485a 100644
> --- a/lib/i915/gem_scheduler.c
> +++ b/lib/i915/gem_scheduler.c
> @@ -90,6 +90,19 @@ bool gem_scheduler_has_ctx_priority(int fd)
>   		I915_SCHEDULER_CAP_PRIORITY;
>   }
>   
> +/**
> + * gem_scheduler_has_ctx_priority:

s/ctx/static/

LGTM apart from this.

Daniele

> + * @fd: open i915 drm file descriptor
> + *
> + * Feature test macro to query whether the driver supports priority assigned
> + * from user space are statically mapping into 3 buckets.
> + */
> +bool gem_scheduler_has_static_priority(int fd)
> +{
> +	return gem_scheduler_capability(fd) &
> +		I915_SCHEDULER_CAP_STATIC_PRIORITY_MAP;
> +}
> +
>   /**
>    * gem_scheduler_has_preemption:
>    * @fd: open i915 drm file descriptor
> diff --git a/lib/i915/gem_scheduler.h b/lib/i915/gem_scheduler.h
> index d43e84bd2..b00804f70 100644
> --- a/lib/i915/gem_scheduler.h
> +++ b/lib/i915/gem_scheduler.h
> @@ -29,6 +29,7 @@
>   unsigned gem_scheduler_capability(int fd);
>   bool gem_scheduler_enabled(int fd);
>   bool gem_scheduler_has_ctx_priority(int fd);
> +bool gem_scheduler_has_static_priority(int fd);
>   bool gem_scheduler_has_preemption(int fd);
>   bool gem_scheduler_has_semaphores(int fd);
>   bool gem_scheduler_has_engine_busy_stats(int fd);
> diff --git a/tests/i915/gem_exec_schedule.c b/tests/i915/gem_exec_schedule.c
> index e5fb45982..f03842478 100644
> --- a/tests/i915/gem_exec_schedule.c
> +++ b/tests/i915/gem_exec_schedule.c
> @@ -1344,8 +1344,7 @@ static void reorder(int fd, const intel_ctx_cfg_t *cfg,
>   static void promotion(int fd, const intel_ctx_cfg_t *cfg, unsigned ring)
>   {
>   	IGT_CORK_FENCE(cork);
> -	uint32_t result, dep;
> -	uint32_t result_read, dep_read;
> +	uint32_t result, dep, dep_read;
>   	const intel_ctx_t *ctx[3];
>   	int fence;
>   
> @@ -1353,10 +1352,10 @@ static void promotion(int fd, const intel_ctx_cfg_t *cfg, unsigned ring)
>   	gem_context_set_priority(fd, ctx[LO]->id, MIN_PRIO);
>   
>   	ctx[HI] = intel_ctx_create(fd, cfg);
> -	gem_context_set_priority(fd, ctx[HI]->id, 0);
> +	gem_context_set_priority(fd, ctx[HI]->id, MAX_PRIO);
>   
>   	ctx[NOISE] = intel_ctx_create(fd, cfg);
> -	gem_context_set_priority(fd, ctx[NOISE]->id, MIN_PRIO/2);
> +	gem_context_set_priority(fd, ctx[NOISE]->id, 0);
>   
>   	result = gem_create(fd, 4096);
>   	dep = gem_create(fd, 4096);
> @@ -1383,11 +1382,9 @@ static void promotion(int fd, const intel_ctx_cfg_t *cfg, unsigned ring)
>   	dep_read = __sync_read_u32(fd, dep, 0);
>   	gem_close(fd, dep);
>   
> -	result_read = __sync_read_u32(fd, result, 0);
>   	gem_close(fd, result);
>   
>   	igt_assert_eq_u32(dep_read, ctx[HI]->id);
> -	igt_assert_eq_u32(result_read, ctx[NOISE]->id);
>   
>   	intel_ctx_destroy(fd, ctx[NOISE]);
>   	intel_ctx_destroy(fd, ctx[LO]);
> @@ -2963,19 +2960,25 @@ igt_main
>   			test_each_engine_store("preempt-other-chain", fd, ctx, e)
>   				preempt_other(fd, &ctx->cfg, e->flags, CHAIN);
>   
> -			test_each_engine_store("preempt-queue", fd, ctx, e)
> -				preempt_queue(fd, &ctx->cfg, e->flags, 0);
> +			test_each_engine_store("preempt-engines", fd, ctx, e)
> +				preempt_engines(fd, e, 0);
>   
> -			test_each_engine_store("preempt-queue-chain", fd, ctx, e)
> -				preempt_queue(fd, &ctx->cfg, e->flags, CHAIN);
> -			test_each_engine_store("preempt-queue-contexts", fd, ctx, e)
> -				preempt_queue(fd, &ctx->cfg, e->flags, CONTEXTS);
> +			igt_subtest_group {
> +				igt_fixture {
> +					igt_require(!gem_scheduler_has_static_priority(fd));
> +				}
>   
> -			test_each_engine_store("preempt-queue-contexts-chain", fd, ctx, e)
> -				preempt_queue(fd, &ctx->cfg, e->flags, CONTEXTS | CHAIN);
> +				test_each_engine_store("preempt-queue", fd, ctx, e)
> +					preempt_queue(fd, &ctx->cfg, e->flags, 0);
>   
> -			test_each_engine_store("preempt-engines", fd, ctx, e)
> -				preempt_engines(fd, e, 0);
> +				test_each_engine_store("preempt-queue-chain", fd, ctx, e)
> +					preempt_queue(fd, &ctx->cfg, e->flags, CHAIN);
> +				test_each_engine_store("preempt-queue-contexts", fd, ctx, e)
> +					preempt_queue(fd, &ctx->cfg, e->flags, CONTEXTS);
> +
> +				test_each_engine_store("preempt-queue-contexts-chain", fd, ctx, e)
> +					preempt_queue(fd, &ctx->cfg, e->flags, CONTEXTS | CHAIN);
> +			}
>   
>   			igt_subtest_group {
>   				igt_hang_t hang;
> @@ -3017,11 +3020,17 @@ igt_main
>   		test_each_engine_store("wide", fd, ctx, e)
>   			wide(fd, &ctx->cfg, e->flags);
>   
> -		test_each_engine_store("reorder-wide", fd, ctx, e)
> -			reorder_wide(fd, &ctx->cfg, e->flags);
> -
>   		test_each_engine_store("smoketest", fd, ctx, e)
>   			smoketest(fd, &ctx->cfg, e->flags, 5);
> +
> +		igt_subtest_group {
> +			igt_fixture {
> +				igt_require(!gem_scheduler_has_static_priority(fd));
> +			}
> +
> +			test_each_engine_store("reorder-wide", fd, ctx, e)
> +				reorder_wide(fd, &ctx->cfg, e->flags);
> +		}
>   	}
>   
>   	igt_subtest_group {