Difference between revisions of "OpenMP in Small Bites/Tasking"

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OpenMP in Small Bites/Tasking
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== Quiz ==
 
== Quiz ==
 +
{{hidden begin
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|title = 1. What is the default data scoping of a variable in a task scope? Hint: Assume that the variable is declared before the task region, but in the same function.
 +
}}
 +
<quiz display=simple>
 +
{
 +
|type="()"}
 +
- Always <code>firstprivate</code>.
 +
|| Wrong.
 +
+ <code>firstprivate</code> unless shared in the enclosing context.
 +
|| Correct.
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- <code>shared</code> unless fristprivate in the enclosing context.
 +
|| Correct.
 +
</quiz>
 +
{{hidden end}}
 +
 +
{{hidden begin
 +
|title = 2. Which tasks are synchronized with by a <code>taskyield</code> construct?
 +
}}
 +
<quiz display=simple>
 +
{
 +
|type="()"}
 +
- All tasks of the same thread team.
 +
||
 +
- All desendant tasks.
 +
||
 +
+ The direct child tasks.
 +
||
 +
</quiz>
 +
{{hidden end}}
 +
 +
{{hidden begin
 +
|title = 3. Why can it be benficial for the performance to use cut-off strategies for task-based OpenMP programs?
 +
}}
 +
<quiz display=simple>
 +
{
 +
|type="()"}
 +
+ It can avoid overhead caused by too fine-grained tasks.
 +
|| Correct.
 +
- It can synchonize tasks faster.
 +
|| Wrong.
 +
- It can accelerate task stealing be enforcing one task queue per thread.
 +
|| Wrong.
 +
</quiz>
 +
{{hidden end}}

Revision as of 17:00, 30 November 2020

Tutorial
Title: OpenMP in Small Bites
Provider: HPC.NRW

Contact: tutorials@hpc.nrw
Type: Multi-part video
Topic Area: Programming Paradigms
License: CC-BY-SA
Syllabus

1. Overview
2. Worksharing
3. Data Scoping
4. False Sharing
5. Tasking
6. Tasking and Data Scoping
7. Tasking and Synchronization
8. Loops and Tasks
9. Tasking Example: Sudoku Solver
10. Task Scheduling
11. Non-Uniform Memory Access

Video

Quiz

1. What is the default data scoping of a variable in a task scope? Hint: Assume that the variable is declared before the task region, but in the same function.

Always firstprivate.
firstprivate unless shared in the enclosing context.
shared unless fristprivate in the enclosing context.

2. Which tasks are synchronized with by a taskyield construct?

All tasks of the same thread team.
All desendant tasks.
The direct child tasks.

3. Why can it be benficial for the performance to use cut-off strategies for task-based OpenMP programs?

It can avoid overhead caused by too fine-grained tasks.
It can synchonize tasks faster.
It can accelerate task stealing be enforcing one task queue per thread.

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