[Intel-gfx] [igt-dev] [PATCH i-g-t v3] i915/gem_exec_balancer: Randomise bonded submission

Chris Wilson chris at chris-wilson.co.uk
Fri May 29 15:13:46 UTC 2020


Quoting Tvrtko Ursulin (2020-05-29 16:08:25)
> 
> On 29/05/2020 14:58, 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.
> > 
> > v2: Test both immediate submission and fenced submission
> > v3: Copy-n-paste a single context variant
> > 
> > Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> > Cc: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> > ---
> >   tests/i915/gem_exec_balancer.c | 341 +++++++++++++++++++++++++++++++++
> >   1 file changed, 341 insertions(+)
> > 
> > diff --git a/tests/i915/gem_exec_balancer.c b/tests/i915/gem_exec_balancer.c
> > index 80ae82416..07fe45920 100644
> > --- a/tests/i915/gem_exec_balancer.c
> > +++ b/tests/i915/gem_exec_balancer.c
> > @@ -1154,6 +1154,342 @@ static void bonded_semaphore(int i915)
> >       gem_context_destroy(i915, ctx);
> >   }
> >   
> > +static void __bonded_pair(int i915,
> > +                       const struct i915_engine_class_instance *siblings,
> > +                       unsigned int count,
> > +                       unsigned int flags,
> > +                       unsigned long *out)
> > +#define B_FENCE 0x1
> > +#define B_HOSTILE 0x2
> > +#define B_MANY 0x4
> > +{
> > +     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;
> > +     unsigned int spinner;
> > +     igt_spin_t *a;
> > +     int timeline;
> > +     uint32_t A;
> > +
> > +     srandom(getpid());
> > +
> > +     spinner = IGT_SPIN_POLL_RUN;
> > +     if (flags & B_HOSTILE)
> > +             spinner |= IGT_SPIN_NO_PREEMPTION;
> > +
> > +     A = gem_context_create(i915);
> > +     set_load_balancer(i915, A, siblings, count, NULL);
> > +     a = igt_spin_new(i915, A, .flags = spinner);
> > +     igt_spin_end(a);
> > +     gem_sync(i915, a->handle);
> > +
> > +     timeline = sw_sync_timeline_create();
> > +
> > +     igt_until_timeout(2) {
> > +             unsigned int master;
> > +             int fence;
> > +
> > +             master = 1;
> > +             if (flags & B_MANY)
> > +                     master = rand() % count + 1;
> > +
> > +             fence = -1;
> > +             if (flags & B_FENCE)
> > +                     fence = sw_sync_timeline_create_fence(timeline,
> > +                                                           cycles + 1);
> > +
> > +             igt_spin_reset(a);
> > +             a->execbuf.flags = master | I915_EXEC_FENCE_OUT;
> > +             if (fence != -1) {
> > +                     a->execbuf.rsvd2 = fence;
> > +                     a->execbuf.flags |= I915_EXEC_FENCE_IN;
> > +             }
> > +             gem_execbuf_wr(i915, &a->execbuf);
> > +
> > +             batch.handle = create_semaphore_to_spinner(i915, a);
> > +             execbuf.rsvd1 = a->execbuf.rsvd1;
> > +             execbuf.rsvd2 = a->execbuf.rsvd2 >> 32;
> > +             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);
> > +
> > +             if (fence != -1) {
> > +                     sw_sync_timeline_inc(timeline, 1);
> > +                     close(fence);
> > +             }
> > +             close(a->execbuf.rsvd2 >> 32);
> > +
> > +             gem_sync(i915, a->handle);
> > +
> > +             cycles++;
> > +     }
> > +
> > +     close(timeline);
> > +     igt_spin_free(i915, a);
> > +     gem_context_destroy(i915, A);
> > +
> > +     *out = cycles;
> > +}
> > +
> > +static void bonded_pair(int i915)
> > +{
> > +     static const unsigned int phases[] = {
> > +             0,
> > +             B_FENCE,
> > +             B_MANY,
> > +             B_HOSTILE,
> > +             B_HOSTILE | B_FENCE,
> > +     };
> > +     unsigned long *cycles;
> > +
> > +     /*
> > +      * 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));
> > +
> > +     cycles = mmap(0, 4096, PROT_WRITE, MAP_SHARED | MAP_ANON, -1, 0);
> > +
> > +     for (int class = 0; class < 32; class++) {
> > +             struct i915_engine_class_instance *siblings;
> > +             unsigned int count;
> > +
> > +             siblings = list_engines(i915, 1u << class, &count);
> > +             if (count < 2)
> > +                     continue;
> > +
> > +             igt_info("Class %u, 1 thread\n", class);
> > +             for (int i = 0; i < ARRAY_SIZE(phases); i++) {
> > +                     cycles[0] = 0;
> > +                     __bonded_pair(i915,
> > +                                   siblings, count,
> > +                                   phases[i],
> > +                                   &cycles[0]);
> > +                     gem_quiescent_gpu(i915);
> > +                     igt_info("%s %s %s submission, %lu cycles\n",
> > +                              phases[i] & B_HOSTILE ? "Non-preemptible" : "Preemptible",
> > +                              phases[i] & B_MANY ? "many-master" : "single-master",
> > +                              phases[i] & B_FENCE ? "fenced" : "immediate",
> > +                              cycles[0]);
> > +             }
> > +
> > +             igt_info("Class %u, %d threads\n", class, count + 1);
> > +             for (int i = 0; i < ARRAY_SIZE(phases); i++) {
> > +                     memset(cycles, 0, (count + 1) * sizeof(*cycles));
> > +                     igt_fork(child, count + 1)
> > +                             __bonded_pair(i915,
> > +                                           siblings, count,
> > +                                           phases[i],
> > +                                           &cycles[child]);
> > +                     igt_waitchildren();
> > +                     gem_quiescent_gpu(i915);
> > +
> > +                     for (int child = 1; child < count + 1; child++)
> > +                             cycles[0] += cycles[child];
> > +
> > +                     igt_info("%s %s %s submission, %lu cycles\n",
> > +                              phases[i] & B_HOSTILE ? "Non-preemptible" : "Preemptible",
> > +                              phases[i] & B_MANY ? "many-master" : "single-master",
> > +                              phases[i] & B_FENCE ? "fenced" : "immediate",
> > +                              cycles[0]);
> > +             }
> > +             free(siblings);
> > +     }
> > +
> > +     munmap(cycles, 4096);
> > +}
> > +
> > +static void __bonded_dual(int i915,
> > +                       const struct i915_engine_class_instance *siblings,
> > +                       unsigned int count,
> > +                       unsigned int flags,
> > +                       unsigned long *out)
> > +{
> > +     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;
> > +     unsigned int spinner;
> > +     igt_spin_t *a, *b;
> > +     int timeline;
> > +     uint32_t A, B;
> > +
> > +     srandom(getpid());
> > +
> > +     spinner = IGT_SPIN_POLL_RUN;
> > +     if (flags & B_HOSTILE)
> > +             spinner |= IGT_SPIN_NO_PREEMPTION;
> > +
> > +     A = gem_context_create(i915);
> > +     set_load_balancer(i915, A, siblings, count, NULL);
> > +     a = igt_spin_new(i915, A, .flags = spinner);
> > +     igt_spin_end(a);
> > +     gem_sync(i915, a->handle);
> > +
> > +     B = gem_context_create(i915);
> > +     set_load_balancer(i915, B, siblings, count, NULL);
> > +     b = igt_spin_new(i915, B, .flags = spinner);
> > +     igt_spin_end(b);
> > +     gem_sync(i915, b->handle);
> > +
> > +     timeline = sw_sync_timeline_create();
> > +
> > +     igt_until_timeout(2) {
> > +             unsigned int master;
> > +             int fence;
> > +
> > +             master = 1;
> > +             if (flags & B_MANY)
> > +                     master = rand() % count + 1;
> > +
> > +             fence = -1;
> > +             if (flags & B_FENCE)
> > +                     fence = sw_sync_timeline_create_fence(timeline,
> > +                                                           cycles + 1);
> > +
> > +             igt_spin_reset(a);
> > +             a->execbuf.flags = master | I915_EXEC_FENCE_OUT;
> > +             if (fence != -1) {
> > +                     a->execbuf.rsvd2 = fence;
> > +                     a->execbuf.flags |= I915_EXEC_FENCE_IN;
> > +             }
> > +             gem_execbuf_wr(i915, &a->execbuf);
> > +
> > +             igt_spin_reset(b);
> > +             b->execbuf.flags = master | I915_EXEC_FENCE_OUT;
> > +             if (fence != -1) {
> > +                     b->execbuf.rsvd2 = fence;
> > +                     b->execbuf.flags |= I915_EXEC_FENCE_IN;
> > +             }
> > +             gem_execbuf_wr(i915, &b->execbuf);
> > +
> > +             if (rand() % 1)
> > +                     igt_swap(a, b);
> > +
> > +             batch.handle = create_semaphore_to_spinner(i915, a);
> > +             execbuf.rsvd1 = a->execbuf.rsvd1;
> > +             execbuf.rsvd2 = a->execbuf.rsvd2 >> 32;
> > +             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->execbuf.rsvd2 >> 32;
> > +             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);
> > +
> > +             if (fence != -1) {
> > +                     sw_sync_timeline_inc(timeline, 1);
> > +                     close(fence);
> > +             }
> > +             close(a->execbuf.rsvd2 >> 32);
> > +             close(b->execbuf.rsvd2 >> 32);
> > +
> > +             gem_sync(i915, a->handle);
> > +             gem_sync(i915, b->handle);
> > +
> > +             cycles++;
> > +     }
> > +
> > +     close(timeline);
> > +
> > +     igt_spin_free(i915, a);
> > +     igt_spin_free(i915, b);
> > +
> > +     gem_context_destroy(i915, A);
> > +     gem_context_destroy(i915, B);
> > +
> > +     *out = cycles;
> > +}
> > +
> > +static void bonded_dual(int i915)
> > +{
> > +     static const unsigned int phases[] = {
> > +             0,
> > +             B_FENCE,
> > +             B_MANY,
> > +             B_HOSTILE,
> > +             B_HOSTILE | B_FENCE,
> > +     };
> > +     unsigned long *cycles;
> > +
> > +
> > +     /*
> > +      * This is the same test as bonded_pair() but with the slight extra
> > +      * stress of having two inflight clients and interchanging them
> > +      * in a thread.
> > +      */
> > +     igt_require(gem_scheduler_has_preemption(i915));
> > +
> > +     cycles = mmap(0, 4096, PROT_WRITE, MAP_SHARED | MAP_ANON, -1, 0);
> > +
> > +     for (int class = 0; class < 32; class++) {
> > +             struct i915_engine_class_instance *siblings;
> > +             unsigned int count;
> > +
> > +             siblings = list_engines(i915, 1u << class, &count);
> > +             if (count < 2)
> > +                     continue;
> > +
> > +             igt_info("Class %u, 1 thread\n", class);
> > +             for (int i = 0; i < ARRAY_SIZE(phases); i++) {
> > +                     cycles[0] = 0;
> > +                     __bonded_dual(i915,
> > +                                   siblings, count,
> > +                                   phases[i],
> > +                                   &cycles[0]);
> > +                     gem_quiescent_gpu(i915);
> > +                     igt_info("%s %s %s submission, %lu cycles\n",
> > +                              phases[i] & B_HOSTILE ? "Non-preemptible" : "Preemptible",
> > +                              phases[i] & B_MANY ? "many-master" : "single-master",
> > +                              phases[i] & B_FENCE ? "fenced" : "immediate",
> > +                              cycles[0]);
> > +             }
> > +
> > +             igt_info("Class %u, %d threads\n", class, count + 1);
> > +             for (int i = 0; i < ARRAY_SIZE(phases); i++) {
> > +                     memset(cycles, 0, (count + 1) * sizeof(*cycles));
> > +                     igt_fork(child, count + 1)
> > +                             __bonded_dual(i915,
> > +                                           siblings, count,
> > +                                           phases[i],
> > +                                           &cycles[child]);
> > +                     igt_waitchildren();
> > +                     gem_quiescent_gpu(i915);
> > +
> > +                     for (int child = 1; child < count + 1; child++)
> > +                             cycles[0] += cycles[child];
> > +
> > +                     igt_info("%s %s %s submission, %lu cycles\n",
> > +                              phases[i] & B_HOSTILE ? "Non-preemptible" : "Preemptible",
> > +                              phases[i] & B_MANY ? "many-master" : "single-master",
> > +                              phases[i] & B_FENCE ? "fenced" : "immediate",
> > +                              cycles[0]);
> > +             }
> > +
> > +             free(siblings);
> > +     }
> > +
> > +     munmap(cycles, 4096);
> > +}
> > +
> >   static void __bonded_nohang(int i915, uint32_t ctx,
> >                           const struct i915_engine_class_instance *siblings,
> >                           unsigned int count,
> > @@ -2284,6 +2620,11 @@ igt_main
> >       igt_subtest("bonded-semaphore")
> >               bonded_semaphore(i915);
> >   
> > +     igt_subtest("bonded-pair")
> > +             bonded_pair(i915);
> > +     igt_subtest("bonded-dual")
> > +             bonded_dual(i915);
> > +
> >       igt_fixture {
> >               igt_stop_hang_detector();
> >       }
> > 
> 
> 
> "Runner" (non underscore functions) could have been shared easily but okay:

Copy-n-paste, 2 keypresses. Sharing, many. I was saving Joules but not
electronvolts.
-Chris


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