[PATCH i-g-t] tests/intel/xe_evict: Reduce allocations to maximum working set

[Zbigniew Kempczyński]

Hi Thomas,

here are my questions:

On Fri, Jun 14, 2024 at 05:30:00PM +0200, Thomas Hellström wrote:
> Current xe kmd allows for a maximum working set of VRAM plus
> half of system memory, or if the working set is allowed only in
> VRAM, the working set is limited to VRAM.
> 
> Some subtests attempt to exceed that. Detect when that happens
> and limit the working set accordingly.
> 
> Cc: Matthew Brost <matthew.brost at intel.com>
> Cc: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
> Signed-off-by: Thomas Hellström <thomas.hellstrom at linux.intel.com>
> ---
>  tests/intel/xe_evict.c | 72 ++++++++++++++++++++++++++++++++++--------
>  1 file changed, 59 insertions(+), 13 deletions(-)
> 
> diff --git a/tests/intel/xe_evict.c b/tests/intel/xe_evict.c
> index eebdbc84b..af5e5e5b6 100644
> --- a/tests/intel/xe_evict.c
> +++ b/tests/intel/xe_evict.c
> @@ -458,6 +458,33 @@ static uint64_t calc_bo_size(uint64_t vram_size, int mul, int div)
>  		return (ALIGN(vram_size, SZ_256M)  * mul) / div; /* small-bar */
>  }
>  
> +static unsigned int working_set(uint64_t vram_size, uint64_t system_size,
> +				uint64_t bo_size, unsigned int num_threads,
> +				unsigned int flags)
> +{
> +	uint64_t set_size;
> +	uint64_t total_size;
> +
> +	set_size = (vram_size - 1) / bo_size;

Is that intentional that if vram_size is 0 you're using max u64?
I bet not as total_size is calculated similar and this might return
huge values.

> +
> +	/*
> +	 * Working set resizes also in system?
> +	 * Currently system graphics memory is limited to 50% of total.
> +	 */
> +	if (!(flags & !(THREADED | MULTI_VM)))
> +		set_size += (system_size / 2) / bo_size;

You mean ~ instead of !?

--
Zbigniew

> +
> +	/* All bos must fit in memory, assuming no swapping */
> +	total_size = ((vram_size - 1) / bo_size + system_size / bo_size) /
> +		num_threads;
> +
> +	if (set_size > total_size)
> +		set_size = total_size;
> +
> +	/* bos are only created on half of the execs. */
> +	return set_size * 2;
> +}


> +
>  /**
>   * SUBTEST: evict-%s
>   * Description:  %arg[1] evict test.
> @@ -748,6 +775,7 @@ igt_main
>  		{ NULL },
>  	};
>  	uint64_t vram_size;
> +	uint64_t system_size;
>  	int fd;
>  
>  	igt_fixture {
> @@ -755,14 +783,16 @@ igt_main
>  		igt_require(xe_has_vram(fd));
>  		vram_size = xe_visible_vram_size(fd, 0);
>  		igt_assert(vram_size);
> +		system_size = igt_get_avail_ram_mb() << 20;
>  
>  		/* Test requires SRAM to about as big as VRAM. For example, small-cm creates
>  		 * (448 / 2) BOs with a size (1 / 128) of the total VRAM size. For
>  		 * simplicity ensure the SRAM size >= VRAM before running this test.
>  		 */
> -		igt_skip_on_f(igt_get_avail_ram_mb() < (vram_size >> 20),
> -			      "System memory %lu MiB is less than local memory %lu MiB\n",
> -			      igt_get_avail_ram_mb(), vram_size >> 20);
> +		igt_skip_on_f(system_size < vram_size,
> +			      "System memory %llu MiB is less than local memory %llu MiB\n",
> +			      (unsigned long long)system_size >> 20,
> +			      (unsigned long long)vram_size >> 20);
>  
>  		xe_for_each_engine(fd, hwe)
>  			if (hwe->engine_class != DRM_XE_ENGINE_CLASS_COPY)
> @@ -770,25 +800,41 @@ igt_main
>  	}
>  
>  	for (const struct section *s = sections; s->name; s++) {
> -		igt_subtest_f("evict-%s", s->name)
> -			test_evict(fd, hwe, s->n_exec_queues, s->n_execs,
> -				   calc_bo_size(vram_size, s->mul, s->div),
> +		igt_subtest_f("evict-%s", s->name) {
> +			uint64_t bo_size = calc_bo_size(vram_size, s->mul, s->div);
> +			int ws = working_set(vram_size, system_size, bo_size,
> +					     1, s->flags);
> +
> +			igt_debug("Max working set %d n_execs %d\n", ws, s->n_execs);
> +			test_evict(fd, hwe, s->n_exec_queues,
> +				   min(ws, s->n_execs), bo_size,
>  				   s->flags, NULL);
> +		}
>  	}
>  
>  	for (const struct section_cm *s = sections_cm; s->name; s++) {
> -		igt_subtest_f("evict-%s", s->name)
> -			test_evict_cm(fd, hwe, s->n_exec_queues, s->n_execs,
> -				      calc_bo_size(vram_size, s->mul, s->div),
> +		igt_subtest_f("evict-%s", s->name) {
> +			uint64_t bo_size = calc_bo_size(vram_size, s->mul, s->div);
> +			int ws = working_set(vram_size, system_size, bo_size,
> +					     1, s->flags);
> +
> +			igt_debug("Max working set %d n_execs %d\n", ws, s->n_execs);
> +			test_evict_cm(fd, hwe, s->n_exec_queues,
> +				      min(ws, s->n_execs), bo_size,
>  				      s->flags, NULL);
> +		}
>  	}
>  
>  	for (const struct section_threads *s = sections_threads; s->name; s++) {
> -		igt_subtest_f("evict-%s", s->name)
> +		igt_subtest_f("evict-%s", s->name) {
> +			uint64_t bo_size = calc_bo_size(vram_size, s->mul, s->div);
> +			int ws = working_set(vram_size, system_size, bo_size,
> +					     s->n_threads, s->flags);
> +
> +			igt_debug("Max working set %d n_execs %d\n", ws, s->n_execs);
>  			threads(fd, hwe, s->n_threads, s->n_exec_queues,
> -				 s->n_execs,
> -				 calc_bo_size(vram_size, s->mul, s->div),
> -				 s->flags);
> +				min(ws, s->n_execs), bo_size, s->flags);
> +		}
>  	}
>  
>  	igt_fixture
> -- 
> 2.44.0
>