From 2b4ede5c974228d2dcf02a581a1c7548d1483c3f Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Wed, 23 Jan 2019 00:14:58 +0000 Subject: i915/gem_exec_schedule: Verify that using HW semaphores doesn't block We may use HW semaphores to schedule nearly-ready work such that they are already spinning on the GPU waiting for the completion on another engine. However, we don't want for that spinning task to actually block any real work should it be scheduled. v2: No typeof autos v3: Don't cheat, check gen8 as well Signed-off-by: Chris Wilson Cc: Tvrtko Ursulin Reviewed-by: Tvrtko Ursulin --- tests/i915/gem_exec_schedule.c | 87 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 87 insertions(+) (limited to 'tests/i915') diff --git a/tests/i915/gem_exec_schedule.c b/tests/i915/gem_exec_schedule.c index 4f0577b4..3df319bc 100644 --- a/tests/i915/gem_exec_schedule.c +++ b/tests/i915/gem_exec_schedule.c @@ -48,6 +48,10 @@ #define MAX_CONTEXTS 1024 +#define LOCAL_I915_EXEC_BSD_SHIFT (13) +#define LOCAL_I915_EXEC_BSD_MASK (3 << LOCAL_I915_EXEC_BSD_SHIFT) +#define ENGINE_MASK (I915_EXEC_RING_MASK | LOCAL_I915_EXEC_BSD_MASK) + IGT_TEST_DESCRIPTION("Check that we can control the order of execution"); static inline @@ -320,6 +324,86 @@ static void smoketest(int fd, unsigned ring, unsigned timeout) } } +static uint32_t __batch_create(int i915, uint32_t offset) +{ + const uint32_t bbe = MI_BATCH_BUFFER_END; + uint32_t handle; + + handle = gem_create(i915, ALIGN(offset + 4, 4096)); + gem_write(i915, handle, offset, &bbe, sizeof(bbe)); + + return handle; +} + +static uint32_t batch_create(int i915) +{ + return __batch_create(i915, 0); +} + +static void semaphore_userlock(int i915) +{ + struct drm_i915_gem_exec_object2 obj = { + .handle = batch_create(i915), + }; + igt_spin_t *spin = NULL; + unsigned int engine; + uint32_t scratch; + + igt_require(gem_scheduler_has_semaphores(i915)); + + /* + * Given the use of semaphores to govern parallel submission + * of nearly-ready work to HW, we still want to run actually + * ready work immediately. Without semaphores, the dependent + * work wouldn't be submitted so our ready work will run. + */ + + scratch = gem_create(i915, 4096); + for_each_physical_engine(i915, engine) { + if (!spin) { + spin = igt_spin_batch_new(i915, + .dependency = scratch, + .engine = engine); + } else { + uint64_t saved = spin->execbuf.flags; + + spin->execbuf.flags &= ~ENGINE_MASK; + spin->execbuf.flags |= engine; + + gem_execbuf(i915, &spin->execbuf); + + spin->execbuf.flags = saved; + } + } + igt_require(spin); + gem_close(i915, scratch); + + /* + * On all dependent engines, the request may be executing (busywaiting + * on a HW semaphore) but it should not prevent any real work from + * taking precedence. + */ + scratch = gem_context_create(i915); + for_each_physical_engine(i915, engine) { + struct drm_i915_gem_execbuffer2 execbuf = { + .buffers_ptr = to_user_pointer(&obj), + .buffer_count = 1, + .flags = engine, + .rsvd1 = scratch, + }; + + if (engine == (spin->execbuf.flags & ENGINE_MASK)) + continue; + + gem_execbuf(i915, &execbuf); + } + gem_context_destroy(i915, scratch); + gem_sync(i915, obj.handle); /* to hang unless we can preempt */ + gem_close(i915, obj.handle); + + igt_spin_batch_free(i915, spin); +} + static void reorder(int fd, unsigned ring, unsigned flags) #define EQUAL 1 { @@ -1307,6 +1391,9 @@ igt_main igt_require(gem_scheduler_has_ctx_priority(fd)); } + igt_subtest("semaphore-user") + semaphore_userlock(fd); + igt_subtest("smoketest-all") smoketest(fd, ALL_ENGINES, 30); -- cgit v1.2.3