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

[Zbigniew Kempczyński]

On Mon, Jun 17, 2024 at 09:14:13AM +0200, Zbigniew Kempczyński wrote:
> 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.

Forget about this question, I've found vram size can't be 0 here.

--
Zbigniew

> 
> > +
> > +	/*
> > +	 * 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
> >