[OT] GCC vs Intel C++ compiler benchmark

[Florian Weimer]

Claus Fischer <claus.fischer@clausfischer.com> writes:

> I'm not concerned with that but with the notable OS difference
> between Linux (SuSE 7.3) and Windows (XP Pro). IMHO a CPU bound
> benchmark should see less than 1 % influence from OS and C library.
> The graphics shows roughly 7% better performance on Windows for the
> same (Intel) compiler.
>
> Are there any ABI differences which would justify such a difference?

A few years ago, I noticed the following difference: The Microsoft C
library on Win32 switches the FPU to 64 bit precision.  GNU/Linux uses
80 bit precision, which used to be slower.  Depending on the working
set, VM performance can affect benchmark results, too.  For example,
Windows 95 taints the first-level data cache of the processor
regularly, measurably decreasing performance.

However, I haven't got any current data.