On 27/05/2020 14:14, Chris Wilson wrote:
Randomly submit a paired spinner and its cancellation as a bonded
(submit fence) pair. Apply congestion to the engine with more bonded
pairs to see if the execution order fails. If we prevent a cancellation
from running, then the spinner will remain spinning forever.
Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Cc: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
---
tests/i915/gem_exec_balancer.c | 108 +++++++++++++++++++++++++++++++++
1 file changed, 108 insertions(+)
diff --git a/tests/i915/gem_exec_balancer.c b/tests/i915/gem_exec_balancer.c
index 80ae82416..98715d726 100644
--- a/tests/i915/gem_exec_balancer.c
+++ b/tests/i915/gem_exec_balancer.c
@@ -1154,6 +1154,111 @@ static void bonded_semaphore(int i915)
gem_context_destroy(i915, ctx);
}
+static void __bonded_dual(int i915,
+ const struct i915_engine_class_instance *siblings,
+ unsigned int count)
+{
+ struct drm_i915_gem_exec_object2 batch = {};
+ struct drm_i915_gem_execbuffer2 execbuf = {
+ .buffers_ptr = to_user_pointer(&batch),
+ .buffer_count = 1,
+ };
+ unsigned long cycles = 0;
+ uint32_t A, B;
+
+ A = gem_context_create(i915);
+ set_load_balancer(i915, A, siblings, count, NULL);
+
+ B = gem_context_create(i915);
+ set_load_balancer(i915, B, siblings, count, NULL);
+
+ igt_until_timeout(5) {
+ unsigned int master = rand() % count + 1;
+ int timeline, fence;
+ igt_spin_t *a, *b;
+
+ timeline = sw_sync_timeline_create();
+ fence = sw_sync_timeline_create_fence(timeline, 1);
+
+ a = igt_spin_new(i915, A,
+ .engine = master,
+ .fence = fence,
+ .flags = (IGT_SPIN_FENCE_IN |
+ IGT_SPIN_POLL_RUN |
+ IGT_SPIN_NO_PREEMPTION |
+ IGT_SPIN_FENCE_OUT));
+ b = igt_spin_new(i915, B,
+ .engine = master,
+ .fence = fence,
+ .flags = (IGT_SPIN_FENCE_IN |
+ IGT_SPIN_POLL_RUN |
+ IGT_SPIN_NO_PREEMPTION |
+ IGT_SPIN_FENCE_OUT));
+
+ close(fence);
Does this or close(timeline) releases the submissions?
I suggest a variant without the fence anyway for a slightly different
profile.
+
+ if (rand() % 1)
+ igt_swap(a, b);
+
+ batch.handle = create_semaphore_to_spinner(i915, a);
These will be preemptible right? More so they schedule out on semaphore
interrupt straight away? So I don't see how slaves can be prevented from
running because they always are on a different physical engine.
We would need a test flavour where slave spins non-preemptively until
either the master or CPU signals to stop. Coming up with the exact
scheme to achieve this might be challenging. I can think about this more
tomorrow.
And also I don't know why this would fail with my patch! I'll want to
have a experiment with that tomorrow as well.
Regards,
Tvrtko
+ execbuf.rsvd1 = a->execbuf.rsvd1;
+ execbuf.rsvd2 = a->out_fence;
+ do {
+ execbuf.flags = rand() % count + 1;
+ } while (execbuf.flags == master);
+ execbuf.flags |= I915_EXEC_FENCE_SUBMIT;
+ gem_execbuf(i915, &execbuf);
+ gem_close(i915, batch.handle);
+
+ batch.handle = create_semaphore_to_spinner(i915, b);
+ execbuf.rsvd1 = b->execbuf.rsvd1;
+ execbuf.rsvd2 = b->out_fence;
+ do {
+ execbuf.flags = rand() % count + 1;
+ } while (execbuf.flags == master);
+ execbuf.flags |= I915_EXEC_FENCE_SUBMIT;
+ gem_execbuf(i915, &execbuf);
+ gem_close(i915, batch.handle);
+
+ close(timeline);
+
+ gem_sync(i915, a->handle);
+ gem_sync(i915, b->handle);
+
+ igt_spin_free(i915, a);
+ igt_spin_free(i915, b);
+ cycles++;
+ }
+
+ igt_info("%lu cycles\n", cycles);
+
+ gem_context_destroy(i915, A);
+ gem_context_destroy(i915, B);
+}
+
+static void bonded_dual(int i915)
+{
+ /*
+ * The purpose of bonded submission is to execute one or more requests
+ * concurrently. However, the very nature of that requires coordinated
+ * submission across multiple engines.
+ */
+ igt_require(gem_scheduler_has_preemption(i915));
+
+ for (int class = 1; class < 32; class++) {
+ struct i915_engine_class_instance *siblings;
+ unsigned int count;
+
+ siblings = list_engines(i915, 1u << class, &count);
+ if (count > 1) {
+ igt_fork(child, count + 1)
+ __bonded_dual(i915, siblings, count);
+ igt_waitchildren();
+ }
+ free(siblings);
+ }
+}
+
static void __bonded_nohang(int i915, uint32_t ctx,
const struct i915_engine_class_instance *siblings,
unsigned int count,
@@ -2284,6 +2389,9 @@ igt_main
igt_subtest("bonded-semaphore")
bonded_semaphore(i915);
+ igt_subtest("bonded-dual")
+ bonded_dual(i915);
+
igt_fixture {
igt_stop_hang_detector();
}
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