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Re: EGCS vs GCC performance
- To: steffend at glitch dot physics dot colostate dot edu (Dave Steffen)
- Subject: Re: EGCS vs GCC performance
- From: jbuck at synopsys dot com
- Date: Tue, 13 Jan 98 9:36:49 PST
- Cc: egcs at cygnus dot com
> If anybody's interested, I just did a (very) informal performance
> test between EGCS 1.0.1 and GCC 2.7.2. The test involved compiling
> and executing some heavily-templated numerical code on a HP 715
> running HP-UX 9.05.
...
> The result, in a nutshell, is that EGCS outperforms GCC
> significantly in both compile-time and run-time.
HP, if I understand correctly, is the platform that has benefited the
most from the Haifa scheduler. The story isn't as great on some other
platforms; ix86/Pentium performance seems to have actually gotten worse
in some cases according to several reports. But I'm sure this will be
addressed soon.
> I executed "time make" using GCC:
>
> g++ -ansi -frepo -O3 -I/usr/local/lib/TNT -I/usr/local/lib/C++ -c kubo.C
>
> (... etc etc)
>
> real 5m40.990s
> user 4m54.180s
> sys 0m30.970s
>
> A lot of time was used recompiling the source to get the
> templates right; this took seven iterations. (The -frepo flag
> is convenient, but it does take a while the first time.
This is why I dislike -frepo. If you're willing to trade larger
object files (and possibly a larger executable if on your platform
the linker cannot eliminate duplicate functions) in exchange for
much faster compile/link time, just don't use -frepo.