Re: [PATCH i-g-t] tests/pm_rpm tests for set_caching and set_tiling ioctl(s)

[Imre Deak <imre.deak@intel.com>]

On to, 2015-11-26 at 12:55 +0200, Marius Vlad wrote:
> On Wed, Nov 25, 2015 at 10:08:21PM +0200, Imre Deak wrote:
> > On ke, 2015-11-25 at 19:16 +0200, marius.c.vlad@intel.com wrote:
> > > From: Marius Vlad <marius.c.vlad@intel.com>
> > > 
> > > Signed-off-by: Marius Vlad <marius.c.vlad@intel.com>
> > > ---
> > >  tests/pm_rpm.c | 120
> > > +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> > >  1 file changed, 120 insertions(+)
> > > 
> > > diff --git a/tests/pm_rpm.c b/tests/pm_rpm.c
> > > index c4fb19c..157cf29 100644
> > > --- a/tests/pm_rpm.c
> > > +++ b/tests/pm_rpm.c
> > > @@ -1729,6 +1729,120 @@ static void planes_subtest(bool
> > > universal, bool dpms)
> > >  	}
> > >  }
> > >  
> > > +static void pm_test_tiling(void)
> > > +{
> > > +	uint32_t *handles;
> > > +	uint8_t **gem_bufs;
> > > +
> > > +	int max_gem_objs = 0;
> > > +	uint8_t off_bit = 20;
> > > +	uint32_t gtt_obj_max_size = (16 * 1024 * 1024);
> > > +
> > > +	uint32_t i, j, tiling_modes[3] = {
> > > +		I915_TILING_NONE,
> > > +		I915_TILING_X,
> > > +		I915_TILING_Y,
> > > +	};
> > > +	uint32_t ti, sw;
> > > +
> > > +	/* default value */
> > > +	uint32_t stride = 1024;
> > > +
> > > +	/* calculate how many objects we can map */
> > > +	for (j = 1 << off_bit; j <= gtt_obj_max_size; j <<= 1, max_gem_objs++)
> > > +		;
> > 
> > With these sizes we may end up with all objects properly aligned,
> > that's why I suggested smaller objects. Based on
> > I830_FENCE_START_MASK
> > we could allocate for example starting from 16kB to 256kB.
> > 
> 
> Initially, I've tried with smaller sizes, but the assertion(s)
> failed.
> I'll try as you suggested.

Hm, there shouldn't be any asserts. The only practical restriction is
on the stride size which on new platforms should be a multiple of 128
or 512 bytes based on the tiling mode and power-of-two on GEN < 4.

> > > +
> > > +	gem_bufs = calloc(max_gem_objs, sizeof(uint8_t *));
> > > +	handles = malloc(sizeof(uint32_t) * max_gem_objs);
> > 
> > Nitpick: sizeof(*ptr) is safer and you could've used calloc in both
> > cases.
> 
> Indeed.
> 
> > 
> > > +
> > > +	/* map to gtt and store some random data */
> > > +	for (i = 0, j = 1 << off_bit; j <= gtt_obj_max_size; j <<= 1, i++) {
> > > +		handles[i] = gem_create(drm_fd, j);
> > > +		gem_bufs[i] = gem_mmap__gtt(drm_fd, handles[i], j, PROT_WRITE);
> > > +		memset(gem_bufs[i], 0x65, j);
> > > +	}
> > > +
> > > +	/* try to set different tiling for each handle */
> > > +	for (i = 0; i < ARRAY_SIZE(tiling_modes); i++) {
> > > +		disable_all_screens_and_wait(&ms_data);
> > > +
> > > +		for (j = 0; j < max_gem_objs; j++) {
> > > +			gem_set_tiling(drm_fd, handles[j], tiling_modes[i], stride);
> > > +
> > > +			gem_get_tiling(drm_fd, handles[j], &ti, &sw);
> > > +			igt_assert(tiling_modes[i] == ti);
> > > +		}
> > > +
> > > +		enable_one_screen_and_wait(&ms_data);
> > 
> > Ok, but after the second iteration all objects could be properly
> > aligned, so it's better to close/realloc/memset the objects in each
> > iteration.
> 
> Alright. I'll do that.
> 
> > 
> > > +	}
> > > +
> > > +	for (i = 0, j = 1 << off_bit; j <= gtt_obj_max_size; j
> > > <<= 1, i++) {
> > > +		igt_assert(munmap(gem_bufs[i], j) == 0);
> > > +		gem_close(drm_fd, handles[i]);
> > > +	}
> > > +
> > > +	free(gem_bufs);
> > > +	free(handles);
> > > +}
> > > +
> > > +static void pm_test_caching(void)
> > > +{
> > > +	uint32_t *handles;
> > > +	uint8_t **gem_bufs;
> > > +	int8_t has_caching_display = -1;
> > > +
> > > +	uint32_t i, j, got_caching;
> > > +	uint32_t gtt_obj_max_size = (16 * 1024 * 1024);
> > > +	uint32_t cache_levels[3] = {
> > > +		I915_CACHING_NONE,
> > > +		I915_CACHING_CACHED,		/* LLC
> > > caching */
> > > +		I915_CACHING_DISPLAY,		/* eDRAM
> > > caching */
> > > +	};
> > > +
> > > +	int max_gem_objs = 0;
> > > +	uint8_t off_bit = 20;
> > > +
> > > +	for (j = 1 << off_bit; j <= gtt_obj_max_size; j <<= 1,
> > > max_gem_objs++)
> > > +		;
> > 
> > No need to bother about alignment here, so we can just use a single
> > 16kB object for example.
> 
> Alright.
> 
> > 
> > > +
> > > +	gem_bufs = calloc(max_gem_objs, sizeof(uint8_t *));
> > > +	handles = malloc(sizeof(uint32_t) * max_gem_objs);
> > > +
> > > +	for (i = 0, j = 1 << off_bit; j <= gtt_obj_max_size; j
> > > <<= 1, i++) {
> > > +		handles[i] = gem_create(drm_fd, j);
> > > +		gem_bufs[i] = gem_mmap__gtt(drm_fd, handles[i],
> > > j, PROT_WRITE);
> > > +		memset(gem_bufs[i], 0x65, j);
> > > +	}
> > > +
> > > +	/* figure out if we have cache display available on the
> > > platform */
> > > +	gem_set_caching(drm_fd, handles[0],
> > > I915_CACHING_DISPLAY);
> > > +	if (gem_get_caching(drm_fd, handles[0]))
> > 
> > No need to hardcode I915_CACHING_NONE here. Also I liked the
> > original
> > version to check this everywhere better, by accepting both
> > CACHING_DISPLAY and CACHING_NONE as a result.
> 
> I don't think I get it.
> 
> As far as I understand CACHING_DISPLAY will fall-back to CACHING_NONE
> if
> the platform doesn't have support for it. Is there a proper way to
> check
> for this?
> igt_require()/igt_skip_on()/igt_require_f() can indeed be used to
> bypass
> certain test(s), but there has to be a way to determine apriori if
> (indeed)
> the platform supports CACHING_DISPLAY, before asserting the status.

We don't need to skip the test, it's valid on any platform to call the
IOCTL with CACHING_DISPLAY, it may just fall back to CACHING_NONE as
you said. So instead of skipping the test just call the IOCTL
everywhere but allow for both CACHING_DISPLAY and CACHING_NONE as the
result of gem_get_caching().

--Imre

> Most likely this kind of issue has come up in other circumstances...
> 
> > 
> > > +		has_caching_display++;
> > > +
> > > +	for (i = 0; i < ARRAY_SIZE(cache_levels) + has_caching_display; i++) {
> > > +		disable_all_screens_and_wait(&ms_data);
> > > +
> > > +		for (j = 0; j < max_gem_objs; j++) {
> > > +			gem_set_caching(drm_fd, handles[j], cache_levels[i]);
> > > +
> > > +			igt_debug("Verying cache for handle %u, level %u\n", j, i);
> > > +			got_caching = gem_get_caching(drm_fd, handles[j]);
> > > +
> > > +			igt_assert(got_caching == cache_levels[i]);
> > > +		}
> > > +
> > > +		enable_one_screen_and_wait(&ms_data);
> > 
> > The object can be unbound after the IOCTL so you need to do a
> > memset at
> > the begin of each iteration.
> 
> Okay. Will redo and send another try. Thanks for taking to time to
> review!.
> 
> > 
> > > +	}
> > > +
> > > +	for (i = 0, j = 1 << off_bit; j <= gtt_obj_max_size; j
> > > <<= 1, i++) {
> > > +		igt_assert(munmap(gem_bufs[i], j) == 0);
> > > +		gem_close(drm_fd, handles[i]);
> > > +	}
> > > +
> > > +	free(handles);
> > > +	free(gem_bufs);
> > > +}
> > > +
> > >  static void fences_subtest(bool dpms)
> > >  {
> > >  	int i;
> > > @@ -1927,6 +2041,12 @@ int main(int argc, char *argv[])
> > >  	igt_subtest("gem-execbuf-stress-extra-wait")
> > >  		gem_execbuf_stress_subtest(rounds, WAIT_STATUS |
> > > WAIT_EXTRA);
> > >  
> > > +	/* power-wake reference tests */
> > > +	igt_subtest("pm-tiling")
> > > +		pm_test_tiling();
> > > +	igt_subtest("pm-caching")
> > > +		pm_test_caching();
> > > +
> > >  	igt_fixture
> > >  		teardown_environment();
> > >  
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