Skip to content

[SYCL] Reintroduce barrier trivial event for empty in-order queue #20263

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 3 commits into from
Oct 2, 2025
Merged

[SYCL] Reintroduce barrier trivial event for empty in-order queue #20263

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
3 commits
Select commit Hold shift + click to select a range
332febc
[SYCL] Reintroduce barrier trivial event for empty in-order queue
steffenlarsen Oct 1, 2025
c9355e3
Trick unittest to avoid work-around
steffenlarsen Oct 1, 2025
a7b2187
Initialize int to avoid warning
steffenlarsen Oct 1, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
8 changes: 8 additions & 0 deletions sycl/source/queue.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -366,6 +366,14 @@ event queue::ext_oneapi_submit_barrier(const std::vector<event> &WaitList,
!EventImpl.hasCommandGraph();
});

// If we have an empty in-order queue and no dependencies, we can just return
// a trivially finished event.
if (is_in_order() && !impl->hasCommandGraph() && !impl->MIsProfilingEnabled &&
AllEventsEmptyOrNop && ext_oneapi_empty()) {
return detail::createSyclObjFromImpl<event>(
detail::event_impl::create_default_event());
}

if (WaitList.empty() || AllEventsEmptyOrNop)
return submit([=](handler &CGH) { CGH.ext_oneapi_barrier(); }, CodeLoc);
else
Expand Down
10 changes: 10 additions & 0 deletions sycl/test-e2e/InorderQueue/in_order_ext_oneapi_submit_barrier.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -60,6 +60,16 @@ int main() {
Q.wait();
assert(*Res == 10);
}
{
// Test cast 3 - empty queue.
std::cout << "Test 3" << std::endl;
sycl::queue EmptyQ({sycl::property::queue::in_order{}});
auto BarrierEvent = EmptyQ.ext_oneapi_submit_barrier();
assert(
BarrierEvent.get_info<sycl::info::event::command_execution_status>() ==
sycl::info::event_command_status::complete);
BarrierEvent.wait();
}
{
// Test cast 4 - graph.
sycl::queue GQueue{sycl::property::queue::in_order{}};
Expand Down
6 changes: 6 additions & 0 deletions sycl/unittests/Extensions/ExtOneapiBarrierOpt.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -6,6 +6,7 @@
//
//===----------------------------------------------------------------------===//

#include <detail/queue_impl.hpp>
#include <gtest/gtest.h>
#include <helpers/ScopedEnvVar.hpp>
#include <helpers/UrMock.hpp>
Expand Down Expand Up @@ -39,6 +40,11 @@ class ExtOneapiBarrierOptTest : public ::testing::Test {
TEST_F(ExtOneapiBarrierOptTest, EmptyEventTest) {
sycl::queue q1{{sycl::property::queue::in_order()}};

// To avoid current optimizations for empty queues, we trick q1 into thinking
// that it isn't empty.
int dummyInt = 0;
q1.prefetch(&dummyInt, sizeof(int));

mock::getCallbacks().set_after_callback(
"urEnqueueEventsWaitWithBarrierExt",
&redefinedEnqueueEventsWaitWithBarrierExt);
Expand Down
Loading