digitalmars.D.ldc - byLine and readln performance with LDC
I'm seeing dramatically slower runtime performance using byLine
and readln when compiling with LDC than with DMD. Has anyone seen
this behavior?
Example:
import std.stdio: File, KeepTerminator, writeln;
void main(string[] args) {
if (args.length != 2) {
writeln("Provide exactly one filename");
return;
}
auto inputStream = args[1].File();
size_t lc = 0;
foreach (line; inputStream.byLine(KeepTerminator.yes)) {
++lc;
}
writeln(lc);
}
Using a 1.7gb, 37 million line file:
- ldc2 (-release -O): 37 seconds
- dmd (-release -O): 4 seconds
Same results with readln rather than byLine. However, byChunk is
fast, even with small chunks like 40 bytes.
This is using: Mac OS X (10.10.5); DMD 2.068; LDC 0.16.1
--Jon
Dec 08 2015
On Wednesday, 9 December 2015 at 08:43:03 UTC, Kagamin wrote:LDC 0.16.1 is based on DMD 2.067.1Ah, this enhancement: https://issues.dlang.org/show_bug.cgi?id=11810. Thanks, that's a rather significant optimization.
Dec 09 2015








Jon D <jond noreply.com>