P4 support question (-> FAQ?)

[Will Menninger]

Tim,

Can you reveal what compilers you are testing and when/where you might
be publishing the results?  My experience is that on Pentium-III's,
Intel's C compiler (v4.x) beats gcc (2.7, 2.8, 2.95) by 10%-40% margins
(largely double precision floating point codes).  But I also have a
finite element field-solving C++ code where gcc beats Intel and MS VC by
more than a factor of two.  I have noticed that the Intel compiler seems
to do a better job of aligning local variables on the stack to optimize
performance (the P-III apparently likes 16-byte alignments(?)).

-Will


"Tim Prince" writes:

>>[...beginning of thread deleted for brevity...]
>
>I don't expect any changes in scheduling to make major differences in
>performance on P4; gcc already does quite well when P-II optimizations are
>selected.  I'm in the middle of a comparison of efficiency of code
>sequences generated by various compilers; while SSE code is required in
>many situations to make the best of P4, there are situations where gcc
>generates P-II compatible code which is faster than that available from
>commercial compilers.