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Re: [OT] GCC vs Intel C++ compiler benchmark
- From: Florian Weimer <fw at deneb dot enyo dot de>
- To: Claus Fischer <claus dot fischer at clausfischer dot com>
- Cc: gcc at gcc dot gnu dot org
- Date: Sun, 27 Jan 2002 13:45:16 +0100
- Subject: Re: [OT] GCC vs Intel C++ compiler benchmark
- References: <20020127124821.A25764@clausfischer.com>
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.