View source for GPU Tutorial/Open MP

[[Category:Tutorials|GPU Computing (Open Mp)]]<nowiki />
{{DISPLAYTITLE:GPU Computing (Open MP)}}<nowiki />
{{Syllabus Introduction to GPU Computing}}<nowiki />
__TOC__

OpenMP 4.0 and later enables developers to program GPUs in C/C++ and Fortran by means of OpenMP directives. In this tutorial we present the basic OpenMP syntax for GPU offloading and give a step-by-step guide for implementing SAXPY with it.

=== Video === <!--T:5-->

=== Quiz === <!--T:5-->  
{{hidden begin 
|title = 1. Which one of the following OpenMP directives can create a target region on GPU?}}
<quiz display=simple>
{
|type="()"}
- `#pragma omp target gpu`
|| `#pragma omp target gpu` is a syntax error in OpenMP.
- `#pragma omp target acc`
|| + `#pragma omp target acc` is a syntax error in OpenMP.
+ `#pragma omp target`
|| Correct: `#pragma omp target` defines a target region, which is a block of computation that operates on GPU.
</quiz>
{{hidden end}}


{{hidden begin 
|title = 2. The OpenMP `map(to:...)` clause maps variables:}}
<quiz display=simple>
{
|type="()"}
+ from host to device data environment before execution
|| Correct
- from host to device data environment after execution
|| Not correct
- from device to host data environment before execution
|| Not correct
- from device to host data environment after execution
|| Not correct
</quiz>
{{hidden end}}


{{hidden begin 
|title = 3. Which one of the following OpenMP directives can initialize a league of teams for execution on GPU?}}
<quiz display=simple>
{
|type="()"}
- `#pragma omp init teams`
|| `#pragma omp init teams` is a syntax error in OpenMP.
+ `#pragma omp teams`
|| Correct: `#pragma omp teams` creates a league of teams for execution on GPU.
- `#pragma omp gpu teams`
|| `#pragma omp init teams` is a syntax error in OpenMP.
</quiz>
{{hidden end}}


{{hidden begin 
|title = 4. Which one of the following OpenMP directives can distribute iterations of for-loop across GPU threads in the teams?}}
<quiz display=simple>
{
|type="()"}
- `#pragma omp distribute for`
|| `#pragma omp distribute for` is a syntax error in OpenMP.
- `#pragma omp parallel for`
|| `#pragma omp parallel for` only parallelizes the for-loop iterations amongst the threads in one team.
+ `#pragma omp distribute parallel for`
|| Correct: `#pragma omp distribute parallel for` distributes the for-loop iterations across two levels of parallelism, which are the league of teams and the threads in each team.
</quiz>
{{hidden end}}