[igt-dev] [PATCH i-g-t] benchmarks/gem_wsim: Heap allocate VLA structs

Chris Wilson
2019-05-24T07:25:51Z

Apparently VLA structs (e.g. struct { int array[count] }) is a gcc
extension that clang refuses to support as handling memory layout is too
difficult for it.

Move the on-stack VLA to the heap.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
---
benchmarks/gem_wsim.c | 146 +++++++++++++++++++++++++++---------------
1 file changed, 95 insertions(+), 51 deletions(-)

diff --git a/benchmarks/gem_wsim.c b/benchmarks/gem_wsim.c
index e2ffb93a9..0a0032bff 100644
--- a/benchmarks/gem_wsim.c
+++ b/benchmarks/gem_wsim.c
@@ -1441,6 +1441,48 @@ set_ctx_sseu(struct ctx *ctx, uint64_t slice_mask)
return slice_mask;
}

+static size_t sizeof_load_balance(int count)
+{
+ struct i915_context_engines_load_balance *ptr;
+
+ assert(sizeof(ptr->engines[count]) == count * sizeof(ptr->engines[0]));
+ return sizeof(*ptr) + sizeof(ptr->engines[count]);
+}
+
+static struct i915_context_engines_load_balance *
+alloc_load_balance(int count)
+{
+ return calloc(1, sizeof_load_balance(count));
+}
+
+static size_t sizeof_param_engines(int count)
+{
+ struct i915_context_param_engines *ptr;
+
+ assert(sizeof(ptr->engines[count]) == count * sizeof(ptr->engines[0]));
+ return sizeof(*ptr) + sizeof(ptr->engines[count]);
+}
+
+static struct i915_context_param_engines *
+alloc_param_engines(int count)
+{
+ return calloc(1, sizeof_param_engines(count));
+}
+
+static size_t sizeof_engines_bond(int count)
+{
+ struct i915_context_engines_bond *ptr;
+
+ assert(sizeof(ptr->engines[count]) == count * sizeof(ptr->engines[0]));
+ return sizeof(*ptr) + sizeof(ptr->engines[count]);
+}
+
+static struct i915_context_engines_bond *
+alloc_engines_bond(int count)
+{
+ return calloc(1, sizeof_engines_bond(count));
+}
+
static int
prepare_workload(unsigned int id, struct workload *wrk, unsigned int flags)
{
@@ -1676,66 +1718,54 @@ prepare_workload(unsigned int id, struct workload *wrk, unsigned int flags)
}

if (ctx->engine_map) {
- I915_DEFINE_CONTEXT_PARAM_ENGINES(set_engines,
- ctx->engine_map_count + 1);
- I915_DEFINE_CONTEXT_ENGINES_LOAD_BALANCE(load_balance,
- ctx->engine_map_count);
+ struct i915_context_param_engines *set_engines =
+ alloc_param_engines(ctx->engine_map_count + 1);
+ struct i915_context_engines_load_balance *load_balance =
+ alloc_load_balance(ctx->engine_map_count);
struct drm_i915_gem_context_param param = {
.ctx_id = ctx_id,
.param = I915_CONTEXT_PARAM_ENGINES,
- .size = sizeof(set_engines),
- .value = to_user_pointer(&set_engines),
+ .size = sizeof_param_engines(ctx->engine_map_count + 1),
+ .value = to_user_pointer(set_engines),
};
+ struct i915_context_engines_bond *last = NULL;

if (ctx->wants_balance) {
- set_engines.extensions =
- to_user_pointer(&load_balance);
+ set_engines->extensions =
+ to_user_pointer(load_balance);

- memset(&load_balance, 0, sizeof(load_balance));
- load_balance.base.name =
+ load_balance->base.name =
I915_CONTEXT_ENGINES_EXT_LOAD_BALANCE;
- load_balance.num_siblings =
+ load_balance->num_siblings =
ctx->engine_map_count;

for (j = 0; j < ctx->engine_map_count; j++)
- load_balance.engines[j] =
+ load_balance->engines[j] =
get_engine(ctx->engine_map[j]);
- } else {
- set_engines.extensions = 0;
}

/* Reserve slot for virtual engine. */
- set_engines.engines[0].engine_class =
+ set_engines->engines[0].engine_class =
I915_ENGINE_CLASS_INVALID;
- set_engines.engines[0].engine_instance =
+ set_engines->engines[0].engine_instance =
I915_ENGINE_CLASS_INVALID_NONE;

for (j = 1; j <= ctx->engine_map_count; j++)
- set_engines.engines[j] =
+ set_engines->engines[j] =
get_engine(ctx->engine_map[j - 1]);

+ last = NULL;
for (j = 0; j < ctx->bond_count; j++) {
unsigned long mask = ctx->bonds[j].mask;
- I915_DEFINE_CONTEXT_ENGINES_BOND(bond,
- __builtin_popcount(mask));
- struct i915_context_engines_bond *p = NULL, *prev;
+ struct i915_context_engines_bond *bond =
+ alloc_engines_bond(__builtin_popcount(mask));
unsigned int b, e;

- prev = p;
- p = alloca(sizeof(bond));
- assert(p);
- memset(p, 0, sizeof(bond));
-
- if (j == 0)
- load_balance.base.next_extension =
- to_user_pointer(p);
- else if (j < (ctx->bond_count - 1))
- prev->base.next_extension =
- to_user_pointer(p);
+ bond->base.next_extension = to_user_pointer(last);
+ bond->base.name = I915_CONTEXT_ENGINES_EXT_BOND;

- p->base.name = I915_CONTEXT_ENGINES_EXT_BOND;
- p->virtual_index = 0;
- p->master = get_engine(ctx->bonds[j].master);
+ bond->virtual_index = 0;
+ bond->master = get_engine(ctx->bonds[j].master);

for (b = 0, e = 0; mask; e++, mask >>= 1) {
unsigned int idx;
@@ -1743,44 +1773,58 @@ prepare_workload(unsigned int id, struct workload *wrk, unsigned int flags)
if (!(mask & 1))
continue;

- idx = find_engine(&set_engines.engines[1],
+ idx = find_engine(&set_engines->engines[1],
ctx->engine_map_count,
e);
- p->engines[b++] =
- set_engines.engines[1 + idx];
+ bond->engines[b++] =
+ set_engines->engines[1 + idx];
}
+
+ last = bond;
}
+ load_balance->base.next_extension = to_user_pointer(last);

gem_context_set_param(fd, &param);
+
+ while (last) {
+ struct i915_context_engines_bond *next =
+ from_user_pointer(last->base.next_extension);
+ free(last);
+ last = next;
+ }
+ free(load_balance);
+ free(set_engines);
} else if (ctx->wants_balance) {
const unsigned int count = num_engines_in_class(VCS);
- I915_DEFINE_CONTEXT_ENGINES_LOAD_BALANCE(load_balance,
- count);
- I915_DEFINE_CONTEXT_PARAM_ENGINES(set_engines,
- count + 1);
+ struct i915_context_engines_load_balance *load_balance =
+ alloc_load_balance(count);
+ struct i915_context_param_engines *set_engines =
+ alloc_param_engines(count + 1);
struct drm_i915_gem_context_param param = {
.ctx_id = ctx_id,
.param = I915_CONTEXT_PARAM_ENGINES,
- .size = sizeof(set_engines),
- .value = to_user_pointer(&set_engines),
+ .size = sizeof_param_engines(count + 1),
+ .value = to_user_pointer(set_engines),
};

- set_engines.extensions = to_user_pointer(&load_balance);
+ set_engines->extensions = to_user_pointer(load_balance);

- set_engines.engines[0].engine_class =
+ set_engines->engines[0].engine_class =
I915_ENGINE_CLASS_INVALID;
- set_engines.engines[0].engine_instance =
+ set_engines->engines[0].engine_instance =
I915_ENGINE_CLASS_INVALID_NONE;
- fill_engines_class(&set_engines.engines[1], VCS);
+ fill_engines_class(&set_engines->engines[1], VCS);

- memset(&load_balance, 0, sizeof(load_balance));
- load_balance.base.name =
+ load_balance->base.name =
I915_CONTEXT_ENGINES_EXT_LOAD_BALANCE;
- load_balance.num_siblings = count;
+ load_balance->num_siblings = count;

- fill_engines_class(&load_balance.engines[0], VCS);
+ fill_engines_class(&load_balance->engines[0], VCS);

gem_context_set_param(fd, &param);
+
+ free(set_engines);
+ free(load_balance);
}

if (wrk->sseu) {
--
2.20.1