[Intel-gfx] [PATCH igt v2] igt/gem_exec_schedule: Exercise "deep" preemption

Chris Wilson chris at chris-wilson.co.uk
Tue Feb 27 10:44:00 UTC 2018


Quoting Chris Wilson (2018-02-26 15:26:58)
> In investigating the issue with having to force preemption within the
> executing ELSP[], we want to trigger preemption between all elements of
> that array. To that end, we issue a series of requests with different
> priorities to fill the in-flight ELSP[] and then demand preemption into
> the middle of that series. One can think of even more complicated
> reordering requirements of ELSP[], trying to switch between every
> possible combination of permutations. Rather than check all 2 billion
> combinations, be content with a few.
> 
> v2: Add a different pattern for queued requests. Not only do we need to
> inject a request into the middle of a single context with a queue of
> different priority contexts, but we also want a queue of different
> contexts, as they have different patterns of ELSP[] behaviour.
> 
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Mika Kuoppala <mika.kuoppala at intel.com>
> Cc: MichaƂ Winiarski <michal.winiarski at intel.com>

Just nod. :)

Don't mention fMBT.
-Chris

> ---
>  tests/gem_exec_schedule.c | 188 +++++++++++++++++++++++++++++++++++++++++-----
>  1 file changed, 169 insertions(+), 19 deletions(-)
> 
> diff --git a/tests/gem_exec_schedule.c b/tests/gem_exec_schedule.c
> index 8a69ab5c..7f1bda42 100644
> --- a/tests/gem_exec_schedule.c
> +++ b/tests/gem_exec_schedule.c
> @@ -373,13 +373,78 @@ static void preempt(int fd, unsigned ring, unsigned flags)
>         gem_close(fd, result);
>  }
>  
> -static void preempt_other(int fd, unsigned ring)
> +#define CHAIN 0x1
> +#define CONTEXTS 0x2
> +
> +static igt_spin_t *__noise(int fd, uint32_t ctx, int prio, igt_spin_t *spin)
> +{
> +       unsigned other;
> +
> +       gem_context_set_priority(fd, ctx, prio);
> +
> +       for_each_physical_engine(fd, other) {
> +               if (spin == NULL) {
> +                       spin = __igt_spin_batch_new(fd, ctx, other, 0);
> +               } else {
> +                       struct drm_i915_gem_exec_object2 obj = {
> +                               .handle = spin->handle,
> +                       };
> +                       struct drm_i915_gem_execbuffer2 eb = {
> +                               .buffer_count = 1,
> +                               .buffers_ptr = to_user_pointer(&obj),
> +                               .rsvd1 = ctx,
> +                               .flags = other,
> +                       };
> +                       gem_execbuf(fd, &eb);
> +               }
> +       }
> +
> +       return spin;
> +}
> +
> +static void __preempt_other(int fd,
> +                           uint32_t *ctx,
> +                           unsigned int target, unsigned int primary,
> +                           unsigned flags)
>  {
>         uint32_t result = gem_create(fd, 4096);
>         uint32_t *ptr = gem_mmap__gtt(fd, result, 4096, PROT_READ);
> -       igt_spin_t *spin[MAX_ENGINES];
> -       unsigned int other;
> -       unsigned int n, i;
> +       unsigned int n, i, other;
> +
> +       n = 0;
> +       store_dword(fd, ctx[LO], primary,
> +                   result, (n + 1)*sizeof(uint32_t), n + 1,
> +                   0, I915_GEM_DOMAIN_RENDER);
> +       n++;
> +
> +       if (flags & CHAIN) {
> +               for_each_physical_engine(fd, other) {
> +                       store_dword(fd, ctx[LO], other,
> +                                   result, (n + 1)*sizeof(uint32_t), n + 1,
> +                                   0, I915_GEM_DOMAIN_RENDER);
> +                       n++;
> +               }
> +       }
> +
> +       store_dword(fd, ctx[HI], target,
> +                   result, (n + 1)*sizeof(uint32_t), n + 1,
> +                   0, I915_GEM_DOMAIN_RENDER);
> +
> +       igt_debugfs_dump(fd, "i915_engine_info");
> +       gem_set_domain(fd, result, I915_GEM_DOMAIN_GTT, 0);
> +
> +       n++;
> +       for (i = 0; i <= n; i++)
> +               igt_assert_eq_u32(ptr[i], i);
> +
> +       munmap(ptr, 4096);
> +       gem_close(fd, result);
> +}
> +
> +static void preempt_other(int fd, unsigned ring, unsigned int flags)
> +{
> +       unsigned int primary;
> +       igt_spin_t *spin = NULL;
>         uint32_t ctx[3];
>  
>         /* On each engine, insert
> @@ -396,36 +461,97 @@ static void preempt_other(int fd, unsigned ring)
>         gem_context_set_priority(fd, ctx[LO], MIN_PRIO);
>  
>         ctx[NOISE] = gem_context_create(fd);
> +       spin = __noise(fd, ctx[NOISE], 0, NULL);
>  
>         ctx[HI] = gem_context_create(fd);
>         gem_context_set_priority(fd, ctx[HI], MAX_PRIO);
>  
> +       for_each_physical_engine(fd, primary) {
> +               igt_debug("Primary engine: %s\n", e__->name);
> +               __preempt_other(fd, ctx, ring, primary, flags);
> +
> +       }
> +
> +       igt_assert(gem_bo_busy(fd, spin->handle));
> +       igt_spin_batch_free(fd, spin);
> +
> +       gem_context_destroy(fd, ctx[LO]);
> +       gem_context_destroy(fd, ctx[NOISE]);
> +       gem_context_destroy(fd, ctx[HI]);
> +}
> +
> +static void __preempt_queue(int fd,
> +                           unsigned target, unsigned primary,
> +                           unsigned depth, unsigned flags)
> +{
> +       uint32_t result = gem_create(fd, 4096);
> +       uint32_t *ptr = gem_mmap__gtt(fd, result, 4096, PROT_READ);
> +       igt_spin_t *above = NULL, *below = NULL;
> +       unsigned int other, n, i;
> +       int prio = MAX_PRIO;
> +       uint32_t ctx[3] = {
> +               gem_context_create(fd),
> +               gem_context_create(fd),
> +               gem_context_create(fd),
> +       };
> +
> +       for (n = 0; n < depth; n++) {
> +               if (flags & CONTEXTS) {
> +                       gem_context_destroy(fd, ctx[NOISE]);
> +                       ctx[NOISE] = gem_context_create(fd);
> +               }
> +               above = __noise(fd, ctx[NOISE], prio--, above);
> +       }
> +
> +       gem_context_set_priority(fd, ctx[HI], prio--);
> +
> +       for (; n < MAX_ELSP_QLEN; n++) {
> +               if (flags & CONTEXTS) {
> +                       gem_context_destroy(fd, ctx[NOISE]);
> +                       ctx[NOISE] = gem_context_create(fd);
> +               }
> +               below = __noise(fd, ctx[NOISE], prio--, below);
> +       }
> +
> +       gem_context_set_priority(fd, ctx[LO], prio--);
> +
>         n = 0;
> -       for_each_physical_engine(fd, other) {
> -               igt_assert(n < ARRAY_SIZE(spin));
> +       store_dword(fd, ctx[LO], primary,
> +                   result, (n + 1)*sizeof(uint32_t), n + 1,
> +                   0, I915_GEM_DOMAIN_RENDER);
> +       n++;
>  
> -               spin[n] = __igt_spin_batch_new(fd, ctx[NOISE], other, 0);
> -               store_dword(fd, ctx[LO], other,
> -                           result, (n + 1)*sizeof(uint32_t), n + 1,
> -                           0, I915_GEM_DOMAIN_RENDER);
> -               n++;
> +       if (flags & CHAIN) {
> +               for_each_physical_engine(fd, other) {
> +                       store_dword(fd, ctx[LO], other,
> +                                   result, (n + 1)*sizeof(uint32_t), n + 1,
> +                                   0, I915_GEM_DOMAIN_RENDER);
> +                       n++;
> +               }
>         }
> -       store_dword(fd, ctx[HI], ring,
> +
> +       store_dword(fd, ctx[HI], target,
>                     result, (n + 1)*sizeof(uint32_t), n + 1,
>                     0, I915_GEM_DOMAIN_RENDER);
>  
>         igt_debugfs_dump(fd, "i915_engine_info");
> -       gem_set_domain(fd, result, I915_GEM_DOMAIN_GTT, 0);
>  
> -       for (i = 0; i < n; i++) {
> -               igt_assert(gem_bo_busy(fd, spin[i]->handle));
> -               igt_spin_batch_free(fd, spin[i]);
> +       if (above) {
> +               igt_assert(gem_bo_busy(fd, above->handle));
> +               igt_spin_batch_free(fd, above);
>         }
>  
> +       gem_set_domain(fd, result, I915_GEM_DOMAIN_GTT, 0);
> +
>         n++;
>         for (i = 0; i <= n; i++)
>                 igt_assert_eq_u32(ptr[i], i);
>  
> +       if (below) {
> +               igt_assert(gem_bo_busy(fd, below->handle));
> +               igt_spin_batch_free(fd, below);
> +       }
> +
>         gem_context_destroy(fd, ctx[LO]);
>         gem_context_destroy(fd, ctx[NOISE]);
>         gem_context_destroy(fd, ctx[HI]);
> @@ -434,6 +560,16 @@ static void preempt_other(int fd, unsigned ring)
>         gem_close(fd, result);
>  }
>  
> +static void preempt_queue(int fd, unsigned ring, unsigned int flags)
> +{
> +       unsigned other;
> +
> +       for_each_physical_engine(fd, other) {
> +               for (unsigned depth = 0; depth <= MAX_ELSP_QLEN; depth++)
> +                       __preempt_queue(fd, ring, other, depth, flags);
> +       }
> +}
> +
>  static void preempt_self(int fd, unsigned ring)
>  {
>         uint32_t result = gem_create(fd, 4096);
> @@ -981,12 +1117,26 @@ igt_main
>                                         igt_subtest_f("preempt-contexts-%s", e->name)
>                                                 preempt(fd, e->exec_id | e->flags, NEW_CTX);
>  
> -                                       igt_subtest_f("preempt-other-%s", e->name)
> -                                               preempt_other(fd, e->exec_id | e->flags);
> -
>                                         igt_subtest_f("preempt-self-%s", e->name)
>                                                 preempt_self(fd, e->exec_id | e->flags);
>  
> +                                       igt_subtest_f("preempt-other-%s", e->name)
> +                                               preempt_other(fd, e->exec_id | e->flags, 0);
> +
> +                                       igt_subtest_f("preempt-other-chain-%s", e->name)
> +                                               preempt_other(fd, e->exec_id | e->flags, CHAIN);
> +
> +                                       igt_subtest_f("preempt-queue-%s", e->name)
> +                                               preempt_queue(fd, e->exec_id | e->flags, 0);
> +
> +                                       igt_subtest_f("preempt-queue-chain-%s", e->name)
> +                                               preempt_queue(fd, e->exec_id | e->flags, CHAIN);
> +                                       igt_subtest_f("preempt-contexts-%s", e->name)
> +                                               preempt_queue(fd, e->exec_id | e->flags, CONTEXTS);
> +
> +                                       igt_subtest_f("preempt-contexts-chain-%s", e->name)
> +                                               preempt_queue(fd, e->exec_id | e->flags, CONTEXTS | CHAIN);
> +
>                                         igt_subtest_group {
>                                                 igt_hang_t hang;
>  
> -- 
> 2.16.2
> 


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