Mail Archives: djgpp/1998/02/25/10:28:23
On 24 Feb 1998, Rylan wrote:
> I am writing an application that might benefit a lot form intensive
> optimisation. Using -O3 (or -O2 with various switches) does seem to
> help,
How so? Do you mean that your program's speed doesn't change, no
matter if you do or don't use -O2? I find this hard to believe.
Did you try the switches and advice mentioned in the DJGPP FAQ list,
section 14.2?
> but I'm thinking that Pentium opti's might be even better.
In my experience, it depends on the structure of your program. If most of
the time is spent in a small number of hot spots which are tight loops,
then Pentium-specific optimizations might help, perhaps as much as 25% or
even more. But if the CPU usage histogram is flat, you are unlikely to
gain much by using PGCC.
In any case, I would suggest profiling your program first, to see
where does it spend most of the time. See chapter 13 of the FAQ for
more details.
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