[igt-dev] [PATCH igt] test/gem_exec_schedule: Check each engine is an independent timeline

[Tvrtko Ursulin]

On 23/04/2018 14:43, Chris Wilson wrote:
> In the existing ABI, each engine operates its own timeline
> (fence.context) and so should execute independently of any other. If we
> install a blocker on all other engines, that should not affect execution
> on the local engine.
> 
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> ---
>   tests/gem_exec_schedule.c | 90 +++++++++++++++++++++++++++++++++++----
>   1 file changed, 82 insertions(+), 8 deletions(-)
> 
> diff --git a/tests/gem_exec_schedule.c b/tests/gem_exec_schedule.c
> index 5d0f215b2..471275169 100644
> --- a/tests/gem_exec_schedule.c
> +++ b/tests/gem_exec_schedule.c
> @@ -49,9 +49,9 @@
>   
>   IGT_TEST_DESCRIPTION("Check that we can control the order of execution");
>   
> -static void store_dword(int fd, uint32_t ctx, unsigned ring,
> -			uint32_t target, uint32_t offset, uint32_t value,
> -			uint32_t cork, unsigned write_domain)
> +static uint32_t __store_dword(int fd, uint32_t ctx, unsigned ring,
> +			      uint32_t target, uint32_t offset, uint32_t value,
> +			      uint32_t cork, unsigned write_domain)
>   {
>   	const int gen = intel_gen(intel_get_drm_devid(fd));
>   	struct drm_i915_gem_exec_object2 obj[3];
> @@ -100,7 +100,17 @@ static void store_dword(int fd, uint32_t ctx, unsigned ring,
>   	batch[++i] = MI_BATCH_BUFFER_END;
>   	gem_write(fd, obj[2].handle, 0, batch, sizeof(batch));
>   	gem_execbuf(fd, &execbuf);
> -	gem_close(fd, obj[2].handle);
> +
> +	return obj[2].handle;
> +}
> +
> +static void store_dword(int fd, uint32_t ctx, unsigned ring,
> +			uint32_t target, uint32_t offset, uint32_t value,
> +			uint32_t cork, unsigned write_domain)
> +{
> +	gem_close(fd, __store_dword(fd, ctx, ring,
> +				    target, offset, value,
> +				    cork, write_domain));
>   }
>   
>   static uint32_t create_highest_priority(int fd)
> @@ -161,6 +171,64 @@ static void fifo(int fd, unsigned ring)
>   	munmap(ptr, 4096);
>   }
>   
> +static void independent(int fd, unsigned int engine)
> +{
> +	IGT_CORK_HANDLE(cork);
> +	uint32_t scratch, plug, batch;
> +	igt_spin_t *spin = NULL;
> +	unsigned int other;
> +	uint32_t *ptr;
> +
> +	igt_require(engine != 0);
> +
> +	scratch = gem_create(fd, 4096);
> +	plug = igt_cork_plug(&cork, fd);
> +
> +	/* Check that we can submit to engine while all others are blocked */
> +	for_each_physical_engine(fd, other) {
> +		if (other == engine)
> +			continue;
> +
> +		if (spin == NULL) {
> +			spin = __igt_spin_batch_new(fd, 0, other, 0);
> +		} else {
> +			struct drm_i915_gem_exec_object2 obj = {
> +				.handle = spin->handle,
> +			};
> +			struct drm_i915_gem_execbuffer2 eb = {
> +				.buffer_count = 1,
> +				.buffers_ptr = to_user_pointer(&obj),
> +				.flags = other,
> +			};
> +			gem_execbuf(fd, &eb);
> +		}
> +
> +		store_dword(fd, 0, other, scratch, 0, other, plug, 0);
> +	}
> +	igt_require(spin);
> +
> +	/* Same priority, but different timeline (as different engine) */
> +	batch = __store_dword(fd, 0, engine, scratch, 0, engine, plug, 0);
> +
> +	unplug_show_queue(fd, &cork, engine);
> +	gem_close(fd, plug);
> +
> +	gem_sync(fd, batch);
> +	gem_close(fd, batch);

Strictly speaking I think you need to use the poll-able spinner and wait 
on it here, before the busy assert. It's unlikely, but spinners on 
'other' engines are getting submitted async to the store dword batch on 
'engine'.

> +	igt_assert(gem_bo_busy(fd, spin->handle));
> +
> +	ptr = gem_mmap__gtt(fd, scratch, 4096, PROT_READ);
> +	gem_close(fd, scratch);
> +	igt_assert_eq(ptr[0], engine);
> +
> +	igt_spin_batch_free(fd, spin);
> +	gem_quiescent_gpu(fd);
> +
> +	/* And we expect the others to have overwritten us, order unspecified */
> +	igt_assert_neq(ptr[0], engine);
> +	munmap(ptr, 4096);
> +}
> +
>   static void smoketest(int fd, unsigned ring, unsigned timeout)
>   {
>   	const int ncpus = sysconf(_SC_NPROCESSORS_ONLN);
> @@ -1070,10 +1138,16 @@ igt_main
>   			if (e->exec_id == 0)
>   				continue;
>   
> -			igt_subtest_f("fifo-%s", e->name) {
> -				igt_require(gem_ring_has_physical_engine(fd, e->exec_id | e->flags));
> -				igt_require(gem_can_store_dword(fd, e->exec_id) | e->flags);
> -				fifo(fd, e->exec_id | e->flags);
> +			igt_subtest_group {
> +				igt_fixture {
> +					igt_require(gem_ring_has_physical_engine(fd, e->exec_id | e->flags));
> +					igt_require(gem_can_store_dword(fd, e->exec_id) | e->flags);
> +				}
> +
> +				igt_subtest_f("fifo-%s", e->name)
> +					fifo(fd, e->exec_id | e->flags);
> +				igt_subtest_f("independent-%s", e->name)
> +					independent(fd, e->exec_id | e->flags);
>   			}
>   		}
>   	}
> 

Apart from what Antonio already commented, and waiting on spinner, looks 
OK to me.

Regards,

Tvrtko