Re: [PATCH igt v2] igt/gem_exec_schedule: Exercise "deep" preemption

[Mika Kuoppala <mika.kuoppala@linux.intel.com>]

Chris Wilson <chris@chris-wilson.co.uk> writes:

> In investigating the issue with having to force preemption within the
> executing ELSP[], we want to trigger preemption between all elements of
> that array. To that end, we issue a series of requests with different
> priorities to fill the in-flight ELSP[] and then demand preemption into
> the middle of that series. One can think of even more complicated
> reordering requirements of ELSP[], trying to switch between every
> possible combination of permutations. Rather than check all 2 billion
> combinations, be content with a few.
>
> v2: Add a different pattern for queued requests. Not only do we need to
> inject a request into the middle of a single context with a queue of
> different priority contexts, but we also want a queue of different
> contexts, as they have different patterns of ELSP[] behaviour.
>
> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
> Cc: Mika Kuoppala <mika.kuoppala@intel.com>
> Cc: Michał Winiarski <michal.winiarski@intel.com>
> ---
>  tests/gem_exec_schedule.c | 188 +++++++++++++++++++++++++++++++++++++++++-----
>  1 file changed, 169 insertions(+), 19 deletions(-)
>
> diff --git a/tests/gem_exec_schedule.c b/tests/gem_exec_schedule.c
> index 8a69ab5c..7f1bda42 100644
> --- a/tests/gem_exec_schedule.c
> +++ b/tests/gem_exec_schedule.c
> @@ -373,13 +373,78 @@ static void preempt(int fd, unsigned ring, unsigned flags)
>  	gem_close(fd, result);
>  }
>  
> -static void preempt_other(int fd, unsigned ring)
> +#define CHAIN 0x1
> +#define CONTEXTS 0x2
> +
> +static igt_spin_t *__noise(int fd, uint32_t ctx, int prio, igt_spin_t *spin)
> +{
> +	unsigned other;
> +
> +	gem_context_set_priority(fd, ctx, prio);
> +
> +	for_each_physical_engine(fd, other) {
> +		if (spin == NULL) {
> +			spin = __igt_spin_batch_new(fd, ctx, 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),
> +				.rsvd1 = ctx,
> +				.flags = other,
> +			};
> +			gem_execbuf(fd, &eb);
> +		}
> +	}
> +
> +	return spin;
> +}
> +
> +static void __preempt_other(int fd,
> +			    uint32_t *ctx,
> +			    unsigned int target, unsigned int primary,
> +			    unsigned flags)
>  {
>  	uint32_t result = gem_create(fd, 4096);
>  	uint32_t *ptr = gem_mmap__gtt(fd, result, 4096, PROT_READ);
> -	igt_spin_t *spin[MAX_ENGINES];
> -	unsigned int other;
> -	unsigned int n, i;
> +	unsigned int n, i, other;
> +
> +	n = 0;
> +	store_dword(fd, ctx[LO], primary,
> +		    result, (n + 1)*sizeof(uint32_t), n + 1,
> +		    0, I915_GEM_DOMAIN_RENDER);
> +	n++;
> +
> +	if (flags & CHAIN) {
> +		for_each_physical_engine(fd, other) {
> +			store_dword(fd, ctx[LO], other,
> +				    result, (n + 1)*sizeof(uint32_t), n + 1,
> +				    0, I915_GEM_DOMAIN_RENDER);
> +			n++;
> +		}
> +	}
> +
> +	store_dword(fd, ctx[HI], target,
> +		    result, (n + 1)*sizeof(uint32_t), n + 1,
> +		    0, I915_GEM_DOMAIN_RENDER);
> +
> +	igt_debugfs_dump(fd, "i915_engine_info");
> +	gem_set_domain(fd, result, I915_GEM_DOMAIN_GTT, 0);
> +
> +	n++;
> +	for (i = 0; i <= n; i++)
> +		igt_assert_eq_u32(ptr[i], i);
> +
> +	munmap(ptr, 4096);
> +	gem_close(fd, result);
> +}
> +
> +static void preempt_other(int fd, unsigned ring, unsigned int flags)
> +{
> +	unsigned int primary;
> +	igt_spin_t *spin = NULL;
>  	uint32_t ctx[3];
>  
>  	/* On each engine, insert
> @@ -396,36 +461,97 @@ static void preempt_other(int fd, unsigned ring)
>  	gem_context_set_priority(fd, ctx[LO], MIN_PRIO);
>  
>  	ctx[NOISE] = gem_context_create(fd);
> +	spin = __noise(fd, ctx[NOISE], 0, NULL);
>  
>  	ctx[HI] = gem_context_create(fd);
>  	gem_context_set_priority(fd, ctx[HI], MAX_PRIO);
>  
> +	for_each_physical_engine(fd, primary) {
> +		igt_debug("Primary engine: %s\n", e__->name);
> +		__preempt_other(fd, ctx, ring, primary, flags);
> +
> +	}
> +
> +	igt_assert(gem_bo_busy(fd, spin->handle));
> +	igt_spin_batch_free(fd, spin);
> +
> +	gem_context_destroy(fd, ctx[LO]);
> +	gem_context_destroy(fd, ctx[NOISE]);
> +	gem_context_destroy(fd, ctx[HI]);
> +}
> +
> +static void __preempt_queue(int fd,
> +			    unsigned target, unsigned primary,
> +			    unsigned depth, unsigned flags)
> +{
> +	uint32_t result = gem_create(fd, 4096);
> +	uint32_t *ptr = gem_mmap__gtt(fd, result, 4096, PROT_READ);
> +	igt_spin_t *above = NULL, *below = NULL;
> +	unsigned int other, n, i;
> +	int prio = MAX_PRIO;
> +	uint32_t ctx[3] = {
> +		gem_context_create(fd),
> +		gem_context_create(fd),
> +		gem_context_create(fd),
> +	};
> +
> +	for (n = 0; n < depth; n++) {
> +		if (flags & CONTEXTS) {
> +			gem_context_destroy(fd, ctx[NOISE]);
> +			ctx[NOISE] = gem_context_create(fd);
> +		}
> +		above = __noise(fd, ctx[NOISE], prio--, above);
> +	}
> +
> +	gem_context_set_priority(fd, ctx[HI], prio--);
> +
> +	for (; n < MAX_ELSP_QLEN; n++) {
> +		if (flags & CONTEXTS) {
> +			gem_context_destroy(fd, ctx[NOISE]);
> +			ctx[NOISE] = gem_context_create(fd);
> +		}
> +		below = __noise(fd, ctx[NOISE], prio--, below);
> +	}
> +
> +	gem_context_set_priority(fd, ctx[LO], prio--);
> +
>  	n = 0;
> -	for_each_physical_engine(fd, other) {
> -		igt_assert(n < ARRAY_SIZE(spin));
> +	store_dword(fd, ctx[LO], primary,
> +		    result, (n + 1)*sizeof(uint32_t), n + 1,
> +		    0, I915_GEM_DOMAIN_RENDER);
> +	n++;
>  
> -		spin[n] = __igt_spin_batch_new(fd, ctx[NOISE], other, 0);
> -		store_dword(fd, ctx[LO], other,
> -			    result, (n + 1)*sizeof(uint32_t), n + 1,
> -			    0, I915_GEM_DOMAIN_RENDER);
> -		n++;
> +	if (flags & CHAIN) {
> +		for_each_physical_engine(fd, other) {
> +			store_dword(fd, ctx[LO], other,
> +				    result, (n + 1)*sizeof(uint32_t), n + 1,
> +				    0, I915_GEM_DOMAIN_RENDER);
> +			n++;
> +		}
>  	}
> -	store_dword(fd, ctx[HI], ring,
> +
> +	store_dword(fd, ctx[HI], target,
>  		    result, (n + 1)*sizeof(uint32_t), n + 1,
>  		    0, I915_GEM_DOMAIN_RENDER);
>  
>  	igt_debugfs_dump(fd, "i915_engine_info");
> -	gem_set_domain(fd, result, I915_GEM_DOMAIN_GTT, 0);
>  
> -	for (i = 0; i < n; i++) {
> -		igt_assert(gem_bo_busy(fd, spin[i]->handle));
> -		igt_spin_batch_free(fd, spin[i]);
> +	if (above) {
> +		igt_assert(gem_bo_busy(fd, above->handle));
> +		igt_spin_batch_free(fd, above);
>  	}
>  
> +	gem_set_domain(fd, result, I915_GEM_DOMAIN_GTT, 0);
> +
>  	n++;
>  	for (i = 0; i <= n; i++)
>  		igt_assert_eq_u32(ptr[i], i);
>  
> +	if (below) {
> +		igt_assert(gem_bo_busy(fd, below->handle));
> +		igt_spin_batch_free(fd, below);
> +	}
> +
>  	gem_context_destroy(fd, ctx[LO]);
>  	gem_context_destroy(fd, ctx[NOISE]);
>  	gem_context_destroy(fd, ctx[HI]);
> @@ -434,6 +560,16 @@ static void preempt_other(int fd, unsigned ring)
>  	gem_close(fd, result);
>  }
>  
> +static void preempt_queue(int fd, unsigned ring, unsigned int flags)
> +{
> +	unsigned other;
> +
> +	for_each_physical_engine(fd, other) {
> +		for (unsigned depth = 0; depth <= MAX_ELSP_QLEN; depth++)
> +			__preempt_queue(fd, ring, other, depth, flags);
> +	}
> +}
> +
>  static void preempt_self(int fd, unsigned ring)
>  {
>  	uint32_t result = gem_create(fd, 4096);
> @@ -981,12 +1117,26 @@ igt_main
>  					igt_subtest_f("preempt-contexts-%s", e->name)
>  						preempt(fd, e->exec_id | e->flags, NEW_CTX);
>  
> -					igt_subtest_f("preempt-other-%s", e->name)
> -						preempt_other(fd, e->exec_id | e->flags);
> -
>  					igt_subtest_f("preempt-self-%s", e->name)
>  						preempt_self(fd, e->exec_id | e->flags);
>  
> +					igt_subtest_f("preempt-other-%s", e->name)
> +						preempt_other(fd, e->exec_id | e->flags, 0);
> +
> +					igt_subtest_f("preempt-other-chain-%s", e->name)
> +						preempt_other(fd, e->exec_id | e->flags, CHAIN);
> +
> +					igt_subtest_f("preempt-queue-%s", e->name)
> +						preempt_queue(fd, e->exec_id | e->flags, 0);
> +
> +					igt_subtest_f("preempt-queue-chain-%s", e->name)
> +						preempt_queue(fd, e->exec_id | e->flags, CHAIN);
> +					igt_subtest_f("preempt-contexts-%s", e->name)

This will collide with the same name as the test above:
preempt(fd, e->exec_id | e->flags, NEW_CTX);

-Mika

> +						preempt_queue(fd, e->exec_id | e->flags, CONTEXTS);
> +
> +					igt_subtest_f("preempt-contexts-chain-%s", e->name)
> +						preempt_queue(fd, e->exec_id | e->flags, CONTEXTS | CHAIN);
> +
>  					igt_subtest_group {
>  						igt_hang_t hang;
>  
> -- 
> 2.16.2
>
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/intel-gfx
_______________________________________________
Intel-gfx mailing list
Intel-gfx@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/intel-gfx