[igt-dev] [PATCH i-g-t 10/12] i915/gem_exec_balancer: Exercise bonded pairs
Chris Wilson
chris at chris-wilson.co.uk
Wed May 22 12:33:43 UTC 2019
Quoting Tvrtko Ursulin (2019-05-22 13:26:43)
>
> On 22/05/2019 12:37, Chris Wilson wrote:
> > 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.
> >
> > v2: Measure load across all bonded siblings to check we don't
> > miss an accidental execution on another.
> >
> > Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> > ---
> > tests/i915/gem_exec_balancer.c | 277 +++++++++++++++++++++++++++++++--
> > 1 file changed, 262 insertions(+), 15 deletions(-)
> >
> > diff --git a/tests/i915/gem_exec_balancer.c b/tests/i915/gem_exec_balancer.c
> > index 40a2719c0..c76113476 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;
> > }
> > @@ -287,6 +315,74 @@ 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(void)
> > {
> > usleep(20 * 1000); /* 20ms should be enough for ksoftirqd! */
> > @@ -346,6 +442,38 @@ static double measure_min_load(int pmu, unsigned int num, int period_us)
> > return min / (double)d_t;
> > }
> >
> > +static void measure_all_load(int pmu, double *v, unsigned int num, int period_us)
> > +{
> > + uint64_t data[2 + num];
> > + uint64_t d_t, d_v[num];
> > +
> > + kick_kthreads();
> > +
> > + igt_assert_eq(read(pmu, data, sizeof(data)), sizeof(data));
> > + for (unsigned int n = 0; n < num; n++)
> > + d_v[n] = -data[2 + n];
> > + d_t = -data[1];
> > +
> > + usleep(period_us);
> > +
> > + igt_assert_eq(read(pmu, data, sizeof(data)), sizeof(data));
> > +
> > + d_t += data[1];
> > + for (unsigned int n = 0; n < num; n++) {
> > + d_v[n] += data[2 + n];
> > + igt_debug("engine[%d]: %.1f%%\n",
> > + n, d_v[n] / (double)d_t * 100);
> > + v[n] = d_v[n] / (double)d_t;
> > + }
> > +}
> > +
> > +static int add_pmu(int pmu, const struct i915_engine_class_instance *ci)
> > +{
> > + return perf_i915_open_group(I915_PMU_ENGINE_BUSY(ci->engine_class,
> > + ci->engine_instance),
> > + pmu);
> > +}
> > +
> > static void check_individual_engine(int i915,
> > uint32_t ctx,
> > const struct i915_engine_class_instance *ci,
> > @@ -394,7 +522,7 @@ static void individual(int i915)
> > for (int pass = 0; pass < count; pass++) { /* approx. count! */
> > igt_assert(sizeof(*ci) == sizeof(int));
> > igt_permute_array(ci, count, igt_exchange_int);
> > - 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);
> > }
> > @@ -406,6 +534,123 @@ 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 class = 0; class < 32; class++) {
> > + struct i915_engine_class_instance *siblings;
> > + unsigned int count, limit;
> > + uint32_t ctx;
> > + int pmu[16];
> > + int n;
> > +
> > + siblings = list_engines(i915, 1u << class, &count);
> > + if (!siblings)
> > + continue;
> > +
> > + if (count < 2) {
> > + free(siblings);
> > + continue;
> > + }
> > +
> > + master_engines = list_engines(i915, ~(1u << class), &limit);
> > + set_engines(i915, master, master_engines, limit);
> > +
> > + limit = min(count, limit);
> > + igt_assert(limit <= ARRAY_SIZE(bonds));
> > + 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]);
> > +
> > + pmu[0] = -1;
> > + for (n = 0; n < limit; n++)
> > + pmu[n] = add_pmu(pmu[0], &siblings[n]);
>
> But still no checking that the job ran on master. If I am following
> correctly you could easily have something like:
>
> pmu[n] = add_pmu(pmu[0], &master_engines[n]);
> pmu[limit + n] = add_pmu(pmu[0], &siblings[n]);
>
> And check both.
I think it is redundant. We check earlier, and have much more precise
selftest for bonding. The only way we can drive this successfully is if
it behaves, and so it satisfies the requirement of checking the uABI.
-Chris
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