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[subgroups][non_uniform_broadcast] Fix broadcasting index generation (#1680)

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* [subgroups][non_uniform_broadcast] Fix broadcasting index generation

The subgroup size may not be greater than `NR_OF_ACTIVE_WORK_ITEMS`.
Broadcasting index needs to be reduced in that case.

Otherwise, if subgroup size == `NR_OF_ACTIVE_WORK_ITEMS` == 4, then we
will encounter "divide-by-zero" error when evaluating `bcast_index %
(n - NR_OF_ACTIVE_WORK_ITEMS)`.

* Revert "[subgroups][non_uniform_broadcast] Fix broadcasting index generation"

This reverts commit 9bbab539de.

* [subgroups][non_uniform_broadcast] Fix broadcasting index generation

Dynamically activate half of the work items in the current subgroup
instead of hardcoding as `NR_OF_ACTIVE_WORK_ITEMS`.

* Apply suggestion
This commit is contained in:
Yilong Guo
2024-03-13 00:25:06 +08:00
committed by GitHub
parent ee504ba861
commit a045f76eed
3 changed files with 14 additions and 26 deletions
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32
test_conformance/subgroups/subgroup_common_templates.h
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@@ -29,7 +29,7 @@
// subgroup takes only one value from only one chosen (the smallest subgroup ID)
// work_item
// sub_group_non_uniform_broadcast - same as type 0 but
// only 4 work_items from subgroup enter the code (are active)
// only half of work_items from subgroup enter the code (are active)
template <typename Ty, SubgroupsBroadcastOp operation> struct BC
{
static void log_test(const WorkGroupParams &test_params,
@@ -78,24 +78,16 @@ template <typename Ty, SubgroupsBroadcastOp operation> struct BC
int bcast_elseif = 0;
int bcast_index = (int)(genrand_int32(gMTdata) & 0x7fffffff)
% (d > n ? n : d);
int num_of_active_items = n >> 1;
// l - calculate subgroup local id from which value will be
// broadcasted (one the same value for whole subgroup)
if (operation != SubgroupsBroadcastOp::broadcast)
{
// reduce brodcasting index in case of non_uniform and
// last workgroup last subgroup
if (last_subgroup_size && j == nj - 1
&& last_subgroup_size < NR_OF_ACTIVE_WORK_ITEMS)
{
bcast_if = bcast_index % last_subgroup_size;
bcast_elseif = bcast_if;
}
else
{
bcast_if = bcast_index % NR_OF_ACTIVE_WORK_ITEMS;
bcast_elseif = NR_OF_ACTIVE_WORK_ITEMS
+ bcast_index % (n - NR_OF_ACTIVE_WORK_ITEMS);
}
if (num_of_active_items != 0)
bcast_if = bcast_index % num_of_active_items;
if (num_of_active_items != n)
bcast_elseif = num_of_active_items
+ bcast_index % (n - num_of_active_items);
}
for (i = 0; i < n; ++i)
@@ -107,7 +99,7 @@ template <typename Ty, SubgroupsBroadcastOp operation> struct BC
}
else
{
if (i < NR_OF_ACTIVE_WORK_ITEMS)
if (i < num_of_active_items)
{
// index of the third
// element int the vector.
@@ -182,15 +174,15 @@ template <typename Ty, SubgroupsBroadcastOp operation> struct BC
}
// Check result
int num_of_active_items = n >> 1;
if (operation == SubgroupsBroadcastOp::broadcast_first)
{
int lowest_active_id = -1;
for (i = 0; i < n; ++i)
{
lowest_active_id = i < NR_OF_ACTIVE_WORK_ITEMS
? 0
: NR_OF_ACTIVE_WORK_ITEMS;
lowest_active_id =
i < num_of_active_items ? 0 : num_of_active_items;
// findout if broadcasted
// value is the same
tr = mx[ii + lowest_active_id];
@@ -221,7 +213,7 @@ template <typename Ty, SubgroupsBroadcastOp operation> struct BC
}
else
{
if (i < NR_OF_ACTIVE_WORK_ITEMS)
if (i < num_of_active_items)
{ // take index of array where info
// which work_item will be
// broadcast its value is stored