Thanks for the response. In my case, this is not a build issue for the GCC system itself (which according to the post you sent is actually "tuned" for mcpu=i686 along with the rest of the RH 8.0 binaries), but rather the issue I have with it is that the code that the GCC compiler creates is "tuned" for the i386 chip and that this is something that I believe Red Hat should change in the configuration of the pre-compiled GCC system.
I think - given the "average" machine out there - that the RH shipped default GCC compiler(s) should produce code "tuned" for at least i686 processors (eg: -mcpu=i686), not i386 (eg: -mcpu=i386) like it does now. My whole problem is that while RH recognizes the value of this "tuning" flag (see post below), they don't configure the GCC they ship to take advantage of it, nor can I rebuild GCC on RH 8.0 myself because of some config. problem inherit with the RH 8.0 GCC (there was another post yesterday regarding this). ;--- From: https://listman.redhat.com/pipermail/psyche-list/2002-October/003457.html On a different note, the compiler flag -mcpu=xxx is a different story entirely from -march. While -march chooses the instruction set, and thus minimum required machine, and RPM package arch... -mcpu selects instruction sheduling order. The instruction scheduling order is optimized to run the fastest on the arch you tell it. While the instructions are reordered for the given CPU, they remain valid instructions for the -march supplied. So using -mcpu=i686 optimizes binaries for i686 instruction scheduling. This is the default for all of Red Hat Linux. We use i386 compatible instructions (-march=i386) but our entire distro is optimized for i686 CPU's, by using -mcpu=i686 which optimizes the instruction order for i686. ;--- Thanks again for the response, Dave ----- Original Message ----- From: "Gordon Messmer" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Thursday, October 24, 2002 2:18 PM Subject: Re: Changing the default target CPU for the redhat GCC installationon RH8.0. On Wed, 2002-10-23 at 12:41, Dave wrote: > BTW - The RH 8.0 GCC 'as shipped' default target CPU for Intel x86 machines > is i386 and according to the docs. this is used only as an optimization > 'hint' for the compiler Red Hat uses -mcpu=i686 as the default for all of their builds. The optimizations you want are in there... We just went through a very long thread on this subject on the psyche-list. You should be able to find it in the archives, but the most interesting message may be this one: https://listman.redhat.com/pipermail/psyche-list/2002-October/003457.html -- redhat-list mailing list unsubscribe mailto:redhat-list-request@;redhat.com?subject=unsubscribe https://listman.redhat.com/mailman/listinfo/redhat-list -- redhat-list mailing list unsubscribe mailto:redhat-list-request@;redhat.com?subject=unsubscribe https://listman.redhat.com/mailman/listinfo/redhat-list
