Hi,
While writing a test case to compare my new distribution with the block
distribution I ran into some performance problems when having distributed
domains, arrays and domainmaps inside a class.
If domain map, domains and arrays are members of a class, and computing is done
in a method, it seems to generate much more communication than when not using
class. Gets on the second locale are 8022 without classes and 20222 using the
class thing on my computer. --cache-remote reduces communications, but the
ratio of gets (or get_nbs) stays same.
Code demonstrating this problem is as an attachment. I ran the test with two
locales. Notice the number of gets on the second locale when using the class
approach.
Is this just a limitation of chapel implementation, or does the class approach
require some special tricks...?
use BlockDist;
use Random;
use Time;
class TestClass {
const Space = {0..9,0..9};
const domMap = new dmap(new Block(boundingBox=Space));
const dom: domain(2) dmapped domMap = Space;
const inDom: domain(2) dmapped domMap = {1..8,1..8};
var initArr: [dom] real;
var resArr: [dom] real;
proc TestClass() {
fillRandom(initArr, 42*42-1);
writeln("INITIAL ARRAY");
writeln(initArr);
writeln("---------------------------------------------");
}
proc DoSomething() {
for 1..1000 do {
forall i in inDom do {
const k = 0.01;
const (x, y) = i;
resArr(i) = (1 - 4*k)*initArr(x, y) + k*(initArr(x-1,y) + initArr(x+1,y) + initArr(x,y-1) + initArr(x,y+1));
}
initArr = resArr;
}
}
}
{
const TC = new TestClass();
resetCommDiagnostics();
startCommDiagnostics();
TC.DoSomething();
writeln("***********************************************");
writeln("Test Class diagnostics: ");
writeln(getCommDiagnostics());
writeln();
writeln("Result:");
writeln(TC.resArr);
writeln();
}
{
const Space = {0..9,0..9};
const domMap = new dmap(new Block(boundingBox=Space));
const dom: domain(2) dmapped domMap = Space;
const inDom: domain(2) dmapped domMap = {1..8,1..8};
var initArr: [dom] real;
var resArr: [dom] real;
fillRandom(initArr, 42*42-1);
resetCommDiagnostics();
startCommDiagnostics();
for 1..1000 do {
forall i in inDom do {
const k = 0.01;
const (x, y) = i;
resArr(i) = (1 - 4*k)*initArr(x, y) + k*(initArr(x-1,y) + initArr(x+1,y) + initArr(x,y-1) + initArr(x,y+1));
}
initArr = resArr;
}
writeln("***********************************************");
writeln("Without class diagnostics: ");
writeln(getCommDiagnostics());
writeln();
writeln("Result:");
writeln(resArr);
writeln();
}
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