[PATCH i-g-t 14/16] i915/gem_exec_balancer: Exercise bonded pairs

Chris Wilson
2019-05-08T10:09:56Z

The submit-fence + load_balancing apis allow for us to execute a named
pair of engines in parallel; that this by submitting a request to one
engine, we can then use the generated submit-fence to submit a second
request to another engine and have it execute at the same time.
Furthermore, by specifying bonded pairs, we can direct the virtual
engine to use a particular engine in parallel to the first request.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
---
tests/i915/gem_exec_balancer.c | 234 +++++++++++++++++++++++++++++++--
1 file changed, 224 insertions(+), 10 deletions(-)

diff --git a/tests/i915/gem_exec_balancer.c b/tests/i915/gem_exec_balancer.c
index 25195d478..20ad66727 100644
--- a/tests/i915/gem_exec_balancer.c
+++ b/tests/i915/gem_exec_balancer.c
@@ -98,9 +98,35 @@ list_engines(int i915, uint32_t class_mask, unsigned int *out)
return engines;
}

+static int __set_engines(int i915, uint32_t ctx,
+ const struct i915_engine_class_instance *ci,
+ unsigned int count)
+{
+ I915_DEFINE_CONTEXT_PARAM_ENGINES(engines, count);
+ struct drm_i915_gem_context_param p = {
+ .ctx_id = ctx,
+ .param = I915_CONTEXT_PARAM_ENGINES,
+ .size = sizeof(engines),
+ .value = to_user_pointer(&engines)
+ };
+
+ engines.extensions = 0;
+ memcpy(engines.engines, ci, sizeof(engines.engines));
+
+ return __gem_context_set_param(i915, &p);
+}
+
+static void set_engines(int i915, uint32_t ctx,
+ const struct i915_engine_class_instance *ci,
+ unsigned int count)
+{
+ igt_assert_eq(__set_engines(i915, ctx, ci, count), 0);
+}
+
static int __set_load_balancer(int i915, uint32_t ctx,
const struct i915_engine_class_instance *ci,
- unsigned int count)
+ unsigned int count,
+ void *ext)
{
I915_DEFINE_CONTEXT_ENGINES_LOAD_BALANCE(balancer, count);
I915_DEFINE_CONTEXT_PARAM_ENGINES(engines, 1 + count);
@@ -113,6 +139,7 @@ static int __set_load_balancer(int i915, uint32_t ctx,

memset(&balancer, 0, sizeof(balancer));
balancer.base.name = I915_CONTEXT_ENGINES_EXT_LOAD_BALANCE;
+ balancer.base.next_extension = to_user_pointer(ext);

igt_assert(count);
balancer.num_siblings = count;
@@ -131,9 +158,10 @@ static int __set_load_balancer(int i915, uint32_t ctx,

static void set_load_balancer(int i915, uint32_t ctx,
const struct i915_engine_class_instance *ci,
- unsigned int count)
+ unsigned int count,
+ void *ext)
{
- igt_assert_eq(__set_load_balancer(i915, ctx, ci, count), 0);
+ igt_assert_eq(__set_load_balancer(i915, ctx, ci, count, ext), 0);
}

static uint32_t load_balancer_create(int i915,
@@ -143,7 +171,7 @@ static uint32_t load_balancer_create(int i915,
uint32_t ctx;

ctx = gem_context_create(i915);
- set_load_balancer(i915, ctx, ci, count);
+ set_load_balancer(i915, ctx, ci, count, NULL);

return ctx;
}
@@ -288,6 +316,74 @@ static void invalid_balancer(int i915)
}
}

+static void invalid_bonds(int i915)
+{
+ I915_DEFINE_CONTEXT_ENGINES_BOND(bonds[16], 1);
+ I915_DEFINE_CONTEXT_PARAM_ENGINES(engines, 1);
+ struct drm_i915_gem_context_param p = {
+ .ctx_id = gem_context_create(i915),
+ .param = I915_CONTEXT_PARAM_ENGINES,
+ .value = to_user_pointer(&engines),
+ .size = sizeof(engines),
+ };
+ uint32_t handle;
+ void *ptr;
+
+ memset(&engines, 0, sizeof(engines));
+ gem_context_set_param(i915, &p);
+
+ memset(bonds, 0, sizeof(bonds));
+ for (int n = 0; n < ARRAY_SIZE(bonds); n++) {
+ bonds[n].base.name = I915_CONTEXT_ENGINES_EXT_BOND;
+ bonds[n].base.next_extension =
+ n ? to_user_pointer(&bonds[n - 1]) : 0;
+ bonds[n].num_bonds = 1;
+ }
+ engines.extensions = to_user_pointer(&bonds);
+ gem_context_set_param(i915, &p);
+
+ bonds[0].base.next_extension = -1ull;
+ igt_assert_eq(__gem_context_set_param(i915, &p), -EFAULT);
+
+ bonds[0].base.next_extension = to_user_pointer(&bonds[0]);
+ igt_assert_eq(__gem_context_set_param(i915, &p), -E2BIG);
+
+ engines.extensions = to_user_pointer(&bonds[1]);
+ igt_assert_eq(__gem_context_set_param(i915, &p), -E2BIG);
+ bonds[0].base.next_extension = 0;
+ gem_context_set_param(i915, &p);
+
+ handle = gem_create(i915, 4096 * 3);
+ ptr = gem_mmap__gtt(i915, handle, 4096 * 3, PROT_WRITE);
+ gem_close(i915, handle);
+
+ memcpy(ptr + 4096, &bonds[0], sizeof(bonds[0]));
+ engines.extensions = to_user_pointer(ptr) + 4096;
+ gem_context_set_param(i915, &p);
+
+ memcpy(ptr, &bonds[0], sizeof(bonds[0]));
+ bonds[0].base.next_extension = to_user_pointer(ptr);
+ memcpy(ptr + 4096, &bonds[0], sizeof(bonds[0]));
+ gem_context_set_param(i915, &p);
+
+ munmap(ptr, 4096);
+ igt_assert_eq(__gem_context_set_param(i915, &p), -EFAULT);
+
+ bonds[0].base.next_extension = 0;
+ memcpy(ptr + 8192, &bonds[0], sizeof(bonds[0]));
+ bonds[0].base.next_extension = to_user_pointer(ptr) + 8192;
+ memcpy(ptr + 4096, &bonds[0], sizeof(bonds[0]));
+ gem_context_set_param(i915, &p);
+
+ munmap(ptr + 8192, 4096);
+ igt_assert_eq(__gem_context_set_param(i915, &p), -EFAULT);
+
+ munmap(ptr + 4096, 4096);
+ igt_assert_eq(__gem_context_set_param(i915, &p), -EFAULT);
+
+ gem_context_destroy(i915, p.ctx_id);
+}
+
static void kick_kthreads(int period_us)
{
sched_yield();
@@ -397,7 +493,7 @@ static void individual(int i915)

for (int pass = 0; pass < count; pass++) { /* approx. count! */
igt_permute_array(ci, count, igt_exchange_int64);
- set_load_balancer(i915, ctx, ci, count);
+ set_load_balancer(i915, ctx, ci, count, NULL);
for (unsigned int n = 0; n < count; n++)
check_individual_engine(i915, ctx, ci, n);
}
@@ -409,6 +505,115 @@ static void individual(int i915)
gem_quiescent_gpu(i915);
}

+static void bonded(int i915, unsigned int flags)
+#define CORK 0x1
+{
+ I915_DEFINE_CONTEXT_ENGINES_BOND(bonds[16], 1);
+ struct i915_engine_class_instance *master_engines;
+ uint32_t master;
+
+ /*
+ * I915_CONTEXT_PARAM_ENGINE provides an extension that allows us
+ * to specify which engine(s) to pair with a parallel (EXEC_SUBMIT)
+ * request submitted to another engine.
+ */
+
+ master = gem_queue_create(i915);
+
+ memset(bonds, 0, sizeof(bonds));
+ for (int n = 0; n < ARRAY_SIZE(bonds); n++) {
+ bonds[n].base.name = I915_CONTEXT_ENGINES_EXT_BOND;
+ bonds[n].base.next_extension =
+ n ? to_user_pointer(&bonds[n - 1]) : 0;
+ bonds[n].num_bonds = 1;
+ }
+
+ for (int mask = 0; mask < 32; mask++) {
+ unsigned int count, limit;
+ struct i915_engine_class_instance *siblings;
+ uint32_t ctx;
+ int n;
+
+ siblings = list_engines(i915, 1u << mask, &count);
+ if (!siblings)
+ continue;
+
+ if (count < 2) {
+ free(siblings);
+ continue;
+ }
+
+ igt_debug("Found %d engines of class %d\n", count, mask);
+
+ master_engines = list_engines(i915, ~(1u << mask), &limit);
+ set_engines(i915, master, master_engines, limit);
+
+ limit = min(count, limit);
+ for (n = 0; n < limit; n++) {
+ bonds[n].master = master_engines[n];
+ bonds[n].engines[0] = siblings[n];
+ }
+
+ ctx = gem_context_clone(i915,
+ master, I915_CONTEXT_CLONE_VM,
+ I915_CONTEXT_CREATE_FLAGS_SINGLE_TIMELINE);
+ set_load_balancer(i915, ctx, siblings, count, &bonds[limit - 1]);
+
+ for (n = 0; n < limit; n++) {
+ struct drm_i915_gem_execbuffer2 eb;
+ IGT_CORK_HANDLE(cork);
+ igt_spin_t *spin, *plug;
+ double load;
+ int pmu;
+
+ igt_assert(siblings[n].engine_class != master_engines[n].engine_class);
+
+ pmu = perf_i915_open(I915_PMU_ENGINE_BUSY(siblings[n].engine_class,
+ siblings[n].engine_instance));
+
+ plug = NULL;
+ if (flags & CORK) {
+ plug = __igt_spin_new(i915,
+ .ctx = master,
+ .engine = n,
+ .dependency = igt_cork_plug(&cork, i915));
+ }
+
+ spin = __igt_spin_new(i915,
+ .ctx = master,
+ .engine = n,
+ .flags = IGT_SPIN_FENCE_OUT);
+
+ eb = spin->execbuf;
+ eb.rsvd1 = ctx;
+ eb.rsvd2 = spin->out_fence;
+ eb.flags = I915_EXEC_FENCE_SUBMIT;
+ gem_execbuf(i915, &eb);
+
+ if (plug) {
+ igt_cork_unplug(&cork);
+ igt_spin_free(i915, plug);
+ }
+
+ load = measure_load(pmu, 10000);
+ igt_spin_free(i915, spin);
+
+ close(pmu);
+
+ igt_assert_f(load > 0.90,
+ "engine %d (class:instance %d:%d) was found to be only %.1f%% busy\n",
+ n, siblings[n].engine_class, siblings[n].engine_instance,
+ load*100);
+ }
+
+ gem_context_destroy(i915, ctx);
+ free(master_engines);
+ free(siblings);
+ }
+
+ gem_context_destroy(i915, master);
+}
+
static void indicies(int i915)
{
I915_DEFINE_CONTEXT_PARAM_ENGINES(engines, I915_EXEC_RING_MASK + 1);
@@ -856,10 +1061,10 @@ static void semaphore(int i915)
count = ARRAY_SIZE(block);

for (int i = 0; i < count; i++) {
- set_load_balancer(i915, block[i], ci, count);
+ set_load_balancer(i915, block[i], ci, count, NULL);
spin[i] = __igt_spin_new(i915,
- .ctx = block[i],
- .dependency = scratch);
+ .ctx = block[i],
+ .dependency = scratch);
}

/*
@@ -867,7 +1072,7 @@ static void semaphore(int i915)
* or we let the vip through. If not, we hang.
*/
vip = gem_context_create(i915);
- set_load_balancer(i915, vip, ci, count);
+ set_load_balancer(i915, vip, ci, count, NULL);
ping(i915, vip, 0);
gem_context_destroy(i915, vip);

@@ -984,7 +1189,7 @@ static bool has_load_balancer(int i915)
int err;

ctx = gem_context_create(i915);
- err = __set_load_balancer(i915, ctx, &ci, 1);
+ err = __set_load_balancer(i915, ctx, &ci, 1, NULL);
gem_context_destroy(i915, ctx);

return err == 0;
@@ -1010,6 +1215,9 @@ igt_main
igt_subtest("invalid-balancer")
invalid_balancer(i915);

+ igt_subtest("invalid-bonds")
+ invalid_bonds(i915);
+
igt_subtest("individual")
individual(i915);

@@ -1044,6 +1252,12 @@ igt_main
igt_subtest("smoke")
smoketest(i915, 20);

+ igt_subtest("bonded-imm")
+ bonded(i915, 0);
+
+ igt_subtest("bonded-cork")
+ bonded(i915, CORK);
+
igt_fixture {
igt_stop_hang_detector();
}
--
2.20.1