Strange measurements when reproducing issue 5650

[Marco Leise]

Am Wed, 25 Apr 2012 10:34:38 +0200
schrieb "SomeDude" <lovelydear at mailmetrash.com>:

> Discussion here: 
> http://d.puremagic.com/issues/show_bug.cgi?id=5650
> 
> On my Windows box, the following program
> 
> import std.stdio, std.container, std.range;
> 
> void main() {
>      enum int range = 100;
>      enum int n = 1_000_000;
> 
>      auto t = redBlackTree!int(0);
> 
>      for (int i = 0; i < n; i++) {
>          if (i > range)
>              t.removeFront();
>          t.insert(i);
>      }
> 
>      writeln(walkLength(t[]));
>      //writeln(t[]);
> }
> 
> runs in about 1793 ms.
> The strange thing is, if I comment out the writeln line, runtimes 
> are in average *slower* by about 20 ms, with timings varying a 
> little bit more than when the writeln is included.
> 
> How can this be ?

GDC (using DMD 2.057) Linux 64-bit, Core 2 Duo @ 2 Ghz
----------------+-------------------
without writeln |       with writeln
        3.150 s | 3.146 s .. 3,195 s

Besides the fact that my rig seems to be a bit dated, I can't reproduce what you see. Only that the writeln makes the timing less accurate.

-- 
Marco