Files
clang-p2996/openmp/runtime/test/tasking/hidden_helper_task/depend.cpp
Shilei Tian 8442967fe3 [OpenMP] Fix task wait doesn't work as expected in serialized team
As discussed in D107121, task wait doesn't work when a regular task T depends on
a detached task or a hidden helper task T' in a serialized team. The root cause is,
since the team is serialized, the last task will not be tracked by
`td_incomplete_child_tasks`. When T' is finished, it first releases its
dependences, and then decrements its parent counter. So far so good. For the thread
that is running task wait, if at the moment it is still spinning and trying to
execute tasks, it is fine because it can detect the new task and execute it.
However, if it happends to finish the function `flag.execute_tasks(...)`, it will
be broken because `td_incomplete_child_tasks` is 0 now.

In this patch, we update the rule to track children tasks a little bit. If the
task team encounters a proxy task or a hidden helper task, all following tasks
will be tracked.

Reviewed By: AndreyChurbanov

Differential Revision: https://reviews.llvm.org/D107496
2021-08-31 12:15:46 -04:00

130 lines
3.4 KiB
C++

// RUN: %libomp-cxx-compile-and-run
// RUN: %libomp-cxx-compile && env OMP_NUM_THREADS=1 %libomp-run
/*
* This test aims to check whether hidden helper task can work with regular task
* in terms of dependences. It is equivalent to the following code:
*
* #pragma omp parallel
* for (int i = 0; i < N; ++i) {
* int data = -1;
* #pragma omp task shared(data) depend(out: data)
* {
* data = 1;
* }
* #pragma omp hidden helper task shared(data) depend(inout: data)
* {
* data += 2;
* }
* #pragma omp hidden helper task shared(data) depend(inout: data)
* {
* data += 4;
* }
* #pragma omp task shared(data) depend(inout: data)
* {
* data += 8;
* }
* #pragma omp taskwait
* assert(data == 15);
* }
*/
#include "common.h"
extern "C" {
struct kmp_task_t_with_privates {
kmp_task_t task;
};
struct anon {
int32_t *data;
};
}
template <int I>
kmp_int32 omp_task_entry(kmp_int32 gtid, kmp_task_t_with_privates *task) {
auto shareds = reinterpret_cast<anon *>(task->task.shareds);
auto p = shareds->data;
*p += I;
return 0;
}
int main(int argc, char *argv[]) {
constexpr const int N = 1024;
#pragma omp parallel for
for (int i = 0; i < N; ++i) {
int32_t gtid = __kmpc_global_thread_num(nullptr);
int32_t data = 0;
// Task 1
auto task1 = __kmpc_omp_task_alloc(
nullptr, gtid, 1, sizeof(kmp_task_t_with_privates), sizeof(anon),
reinterpret_cast<kmp_routine_entry_t>(omp_task_entry<1>));
auto shareds = reinterpret_cast<anon *>(task1->shareds);
shareds->data = &data;
kmp_depend_info_t depinfo1;
depinfo1.base_addr = reinterpret_cast<intptr_t>(&data);
depinfo1.flag = 2; // OUT
depinfo1.len = 4;
__kmpc_omp_task_with_deps(nullptr, gtid, task1, 1, &depinfo1, 0, nullptr);
// Task 2
auto task2 = __kmpc_omp_target_task_alloc(
nullptr, gtid, 1, sizeof(kmp_task_t_with_privates), sizeof(anon),
reinterpret_cast<kmp_routine_entry_t>(omp_task_entry<2>), -1);
shareds = reinterpret_cast<anon *>(task2->shareds);
shareds->data = &data;
kmp_depend_info_t depinfo2;
depinfo2.base_addr = reinterpret_cast<intptr_t>(&data);
depinfo2.flag = 3; // INOUT
depinfo2.len = 4;
__kmpc_omp_task_with_deps(nullptr, gtid, task2, 1, &depinfo2, 0, nullptr);
// Task 3
auto task3 = __kmpc_omp_target_task_alloc(
nullptr, gtid, 1, sizeof(kmp_task_t_with_privates), sizeof(anon),
reinterpret_cast<kmp_routine_entry_t>(omp_task_entry<4>), -1);
shareds = reinterpret_cast<anon *>(task3->shareds);
shareds->data = &data;
kmp_depend_info_t depinfo3;
depinfo3.base_addr = reinterpret_cast<intptr_t>(&data);
depinfo3.flag = 3; // INOUT
depinfo3.len = 4;
__kmpc_omp_task_with_deps(nullptr, gtid, task3, 1, &depinfo3, 0, nullptr);
// Task 4
auto task4 = __kmpc_omp_task_alloc(
nullptr, gtid, 1, sizeof(kmp_task_t_with_privates), sizeof(anon),
reinterpret_cast<kmp_routine_entry_t>(omp_task_entry<8>));
shareds = reinterpret_cast<anon *>(task4->shareds);
shareds->data = &data;
kmp_depend_info_t depinfo4;
depinfo4.base_addr = reinterpret_cast<intptr_t>(&data);
depinfo4.flag = 3; // INOUT
depinfo4.len = 4;
__kmpc_omp_task_with_deps(nullptr, gtid, task4, 1, &depinfo4, 0, nullptr);
// Wait for all tasks
__kmpc_omp_taskwait(nullptr, gtid);
assert(data == 15);
}
std::cout << "PASS\n";
return 0;
}
// CHECK: PASS