[igt-dev] [PATCH i-g-t v3 10/52] tests/gem_busy: Adopt to use allocator

[Zbigniew Kempczyński]

On Wed, Aug 04, 2021 at 07:07:41PM -0700, Dixit, Ashutosh wrote:
> On Mon, 26 Jul 2021 12:59:44 -0700, Zbigniew Kempczyński wrote:
> >
> > For newer gens we're not able to rely on relocations. Adopt to use
> > offsets acquired from the allocator.
> >
> > Signed-off-by: Zbigniew Kempczyński <zbigniew.kempczynski at intel.com>
> > Cc: Petri Latvala <petri.latvala at intel.com>
> > Cc: Ashutosh Dixit <ashutosh.dixit at intel.com>
> > ---
> >  tests/i915/gem_busy.c | 35 +++++++++++++++++++++++++++++++----
> >  1 file changed, 31 insertions(+), 4 deletions(-)
> >
> > diff --git a/tests/i915/gem_busy.c b/tests/i915/gem_busy.c
> > index f0fca0e8a..51ec5ad04 100644
> > --- a/tests/i915/gem_busy.c
> > +++ b/tests/i915/gem_busy.c
> > @@ -108,6 +108,7 @@ static void semaphore(int fd, const intel_ctx_t *ctx,
> >	uint32_t handle[3];
> >	uint32_t read, write;
> >	uint32_t active;
> > +	uint64_t ahnd = get_reloc_ahnd(fd, ctx->id);
> >	unsigned i;
> >
> >	handle[TEST] = gem_create(fd, 4096);
> > @@ -117,6 +118,7 @@ static void semaphore(int fd, const intel_ctx_t *ctx,
> >	/* Create a long running batch which we can use to hog the GPU */
> >	handle[BUSY] = gem_create(fd, 4096);
> >	spin = igt_spin_new(fd,
> > +			    .ahnd = ahnd,
> >			    .ctx = ctx,
> >			    .engine = e->flags,
> >			    .dependency = handle[BUSY]);
> 
> Missing put_ahnd.

Good catch.

> 
> > @@ -428,6 +442,7 @@ igt_main
> >
> >	igt_subtest_group {
> >		igt_fixture {
> > +			intel_allocator_multiprocess_start();
> >			igt_fork_hang_detector(fd);
> >		}
> >
> > @@ -445,6 +460,21 @@ igt_main
> >			}
> >		}
> >
> 
> Just above here is basic() which doesn't have a fork. Is it ok to do
> intel_allocator_multiprocess_start/stop when we don't have a fork? If yes,
> then can we _always_ do intel_allocator_multiprocess_start/stop rather than
> only when we have fork? Thanks.

intel_allocator_multiprocess_start() creates allocator thread which acts
for children (igt_fork) to alloc/free offsets. If you use alloc/free within
same process (from which thread was spawned) internal structure is mutexed
and no IPCs are called. So only consequence of this here is additional thread
in system/memory (which does nothing for basic() tests). It will be stopped
with intel_allocator_multiprocess_stop().

But for purity test should work without additional dependencies so I'll fix
this - it will be sent in v4.

--
Zbigniew