Search found 9 matches

by achalk
Wed Jul 19, 2017 3:37 am
Forum: Using OpenMP
Topic: Question on Taskgroup (partly related to task reduction)
Replies: 2
Views: 4320

Re: Question on Taskgroup (partly related to task reduction)

That was what I expected but not what I hoped. If we remove the taskgroup, the code I have performs better if spawning the tasks inside a omp do (they are dependency-free, or well, dependency-free of any dependency structure recognised as of OpenMP 5.0 TR) by a reasonable amount. I guess the best op...
by achalk
Fri Jul 14, 2017 3:20 am
Forum: Using OpenMP
Topic: Question on Taskgroup (partly related to task reduction)
Replies: 2
Views: 4320

Question on Taskgroup (partly related to task reduction)

Hi, I have a question about how taskgroup behaves with multiple threads spawning tasks, as I'm struggling slightly with the description in the standard. The standard (OpenMP 5.0 TR) says: The taskgroup construct specifies a wait on completion of child tasks of the current task and their descendent t...
by achalk
Mon May 22, 2017 6:27 am
Forum: TR4 OpenMP 5.0 Preview Discussion
Topic: [suggestions] OpenMP task + OMPT
Replies: 0
Views: 31472

[suggestions] OpenMP task + OMPT

Naming task regions: With the new OMPT interface with OpenMP, it should be possible to develop tools to visualise the computation according to what thread is doing what work (which can be identified from things like the ompt_record_task_create_s.codeptr_ra for tasks for example). It may be useful f...
by achalk
Fri Feb 24, 2017 11:16 am
Forum: Using OpenMP
Topic: Standard compliance - Shared fortran arrays + recursive task
Replies: 1
Views: 2561

Standard compliance - Shared fortran arrays + recursive task

Hi, I'm having an issue with a piece of OpenMP code, where it works with one compiler but not another, and I'm struggling to understand if what I'm doing is unsupported according to the MPI Standard, or if I've made an error. The issue involves task's spawning tasks if some criteria is met, inside o...
by achalk
Tue Oct 11, 2016 10:27 am
Forum: Using OpenMP
Topic: OpenMP task dependencies and array sections
Replies: 2
Views: 3824

Re: OpenMP task dependencies and array sections

Ok thanks. I'll have another think on how to do this then
by achalk
Tue Oct 11, 2016 8:29 am
Forum: Using OpenMP
Topic: OpenMP task dependencies and array sections
Replies: 2
Views: 3824

OpenMP task dependencies and array sections

Hi again. I'm confused as to if I understand how openMP (inout) dependencies on array sections work correctly. My understand would be as follows: If I create a task as follows: #pragma omp depend(inout: a[32:32]) task_function(a); and later: #pragma omp depend(inout: a[0:64]) The latter task should ...
by achalk
Fri Sep 30, 2016 4:25 am
Forum: Using OpenMP
Topic: Race conditions and tasks
Replies: 4
Views: 5119

Re: Race conditions and tasks

Thanks for the detailed reponses Mark, that makes sense now.
by achalk
Thu Sep 29, 2016 1:55 am
Forum: Using OpenMP
Topic: Race conditions and tasks
Replies: 4
Views: 5119

Re: Race conditions and tasks

This code probably doesn't do what you expect, because tasks generated by different threads are not sibling tasks. To make all the tasks sibling tasks, you would need to generate them in a master (or single) construct. If you do this, though, it likely results in less parallelism than is potentiall...
by achalk
Wed Sep 28, 2016 5:49 am
Forum: Using OpenMP
Topic: Race conditions and tasks
Replies: 4
Views: 5119

Race conditions and tasks

Hi, I've been working with tasks a bit and was just wanting to make sure my understanding of how race conditions, tasks and locks work was correct. The first is to do with the depend clause, and just to confirm what I understand the standard to mean - any tasks which have a dependency based on any v...