On Thursday, 24 June 2021 at 21:19:19 UTC, Ali Çehreli wrote:
>On 6/24/21 1:41 PM, seany wrote:
>Is there any way to control the number of CPU cores used in
parallelization ?
Yes. You have to create a task pool explicitly:
import std.parallelism;
void main() {
enum threadCount = 2;
auto myTaskPool = new TaskPool(threadCount);
scope (exit) {
myTaskPool.finish();
}
enum workUnitSize = 1; // Or 42 or something else. :)
foreach (e; myTaskPool.parallel([ 1, 2, 3 ], workUnitSize)) {
// ...
}
}
I've touched on a few parallelism concepts at this point in a presentation:
https://www.youtube.com/watch?v=dRORNQIB2wA&t=1332s
Ali
I tried this .
int[][] pnts ;
pnts.length = fld.length;
enum threadCount = 2;
auto prTaskPool = new TaskPool(threadCount);
scope (exit) {
prTaskPool.finish();
}
enum workUnitSize = 1;
foreach(i, fLine; prTaskPool.parallel(fld, workUnitSize)) {
//....
}
This is throwing random segfaults.
CPU has 2 cores, but usage is not going above 37%
Even much deeper down in program, much further down the line...
And the location of segfault is random.