| Issue |
84180
|
| Summary |
[OMPT] Cancelled tasks schedules
|
| Labels |
new issue
|
| Assignees |
|
| Reporter |
rpereira-dev
|
Something seems wrong with the OMPT `task_schedule` event on tasks whose taskgroup had been cancelled, please see minimal example bellow
LLVM version
```bash
$ clang --version
clang version 19.0.0git (https://github.com/rpereira-dev/llvm-project a64975f9660e02f5f6688f8bcc55daf9eaa99fda)
Target: x86_64-unknown-linux-gnu
Thread model: posix
```
main.c
```C
# include <stdio.h>
# include <unistd.h>
# include <omp.h>
int main(void)
{
# pragma omp parallel
{
# pragma omp single
{
# pragma omp taskgroup
{
# pragma omp task if(0) // A
{
puts("cancelling");
# pragma omp cancel taskgroup
}
# pragma omp task // B
puts("run");
}
}
}
return 0;
}
```
OMPT tool used
```bash
git clone -b llvm/untied-schedule https://github.com/rpereira-dev/ompt-dump.git
```
Compiled and run as
```
clang -Wall -Werror -Wextra -fopenmp main.c
OMP_CANCELLATION=1 OMP_NUM_THREADS=1 OMP_TOOL_LIBRARIES=path/to/libompt_dump.so ./a.out
```
Outputs
```
1 [OMPT] [INFO] OMPT_DUMP: OpenMP 201611 and runtime LLVM OMP version: 5.0.20140926
2 [OMPT] [INFO] Could not register callback 'ompt_callback_device_unload'
3 [OMPT] [INFO] Could not register callback 'ompt_callback_target_map'
4 [OMPT] [INFO] Could not register callback 'ompt_callback_target_map_emi'
5 [OMPT] [INFO] ompt_callback_thread_begin
6 [OMPT] [INFO] ompt_callback_implicit_task(task_data=0x55c84b0b1440)
7 [OMPT] [INFO] ompt_callback_parallel_begin
8 [OMPT] [INFO] ompt_callback_implicit_task(task_data=0x55c84b0b82c0)
9 [OMPT] [INFO] ompt_callback_work
10 [OMPT] [INFO] ompt_callback_sync_region
11 [OMPT] [INFO] ompt_callback_task_create(encountering_task_data=0x55c84b0b82c0, new_task_data=0x55c84b1ba880)
12 [OMPT] [INFO] ompt_callback_task_schedule(prior_task_data=0x55c84b0b82c0, prior_task_status=7, next_task_data=0x55c84b1ba880)
13 cancelling
14 [OMPT] [INFO] ompt_callback_cancel(task_data=0x55c84b1ba880, flags=24)
15 [OMPT] [INFO] ompt_callback_task_schedule(prior_task_data=0x55c84b1ba880, prior_task_status=3, next_task_data=0x55c84b0b82c0)
16 [OMPT] [INFO] ompt_callback_task_create(encountering_task_data=0x55c84b0b82c0, new_task_data=0x55c84b1ba880)
17 [OMPT] [INFO] ompt_callback_cancel(task_data=0x55c84b1ba880, flags=72)
18 [OMPT] [INFO] ompt_callback_task_schedule(prior_task_data=0x55c84b1ba880, prior_task_status=3, next_task_data=0x55c84b0b82c0)
19 [OMPT] [INFO] ompt_callback_sync_region_wait
20 [OMPT] [INFO] ompt_callback_sync_region_wait
21 [OMPT] [INFO] ompt_callback_sync_region
22 [OMPT] [INFO] ompt_callback_work
23 [OMPT] [INFO] ompt_callback_sync_region
24 [OMPT] [INFO] ompt_callback_sync_region_wait
25 [OMPT] [INFO] ompt_callback_sync_region_wait
26 [OMPT] [INFO] ompt_callback_sync_region
27 [OMPT] [INFO] ompt_callback_implicit_task(task_data=0x55c84b0b82c0)
28 [OMPT] [INFO] ompt_callback_parallel_end
29 [OMPT] [INFO] ompt_callback_implicit_task(task_data=0x55c84b0b1440)
30 [OMPT] [INFO] ompt_callback_thread_end
```
Event Line 12 - The thread switches from its implicit (parent) task `0x55a0067a5280` to the explicit task A `0x55a0068a7880`
Event Line 13-14 - The taskgroup is cancelled
Event Line 15 - The thread switches from the explicit task A `0x55a0068a7880` to its implicit (parent) task `0x55a0067a5280`
Event Line 16 - The thread create the task B `0x55a0068a7880`
Event Line 17 - The thread discards the task B `0x55a0068a7880`
Event Line 18 - The thread switches from the explicit task B `0x55a0068a7880` to its implicit (parent) task `0x55a0067a5280` - (**ERROR: the current task is `0x55a0067a5280`**)
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