On Thu, Mar 15, 2007 at 02:47:42AM +0100, Karol Kwiatkowski wrote:
> Gary Kline wrote:
> >     Two quick one for kernel and/or compiler wizards:  first, is
> >     a 400Mz processor considered a 586 (for my KERNELCONF file)?
> That depends on processor architecture rather than clock frequency. Have
> a look at dmesg output - for example, Intel Celeron 400Mhz is a 686
> class processor (I686_CPU in the kernel configuration file):
> % dmesg
> % [...]
> % CPU: Pentium II/Pentium II Xeon/Celeron (400.91-MHz 686-class CPU)
> % [...]

        Dunno anything about the Xeon, but the Kayak is nuilt like a
        tank and has got to be == a 686 also.  I'll check my dmesg 
        too.  --Until very recently, I've gone wit the default (i386??);
        like: how much faster is gcc tweaking going to be?  I guess I'll
        find out!

> >     Second, is it safe to do a buildworld with -O3?  If there are
> >     stability concerns, I'll go with the default when I rebuild my
> >     6.2 systems.
> If you're going to do stability/performance/compatibility tests go
> ahead. In any other situation just stick with the defaults, which on
> 6.2-RELEASE for my Celeron are:
> # (cd /usr/src && make -V CFLAGS )
> -O2 -fno-strict-aliasing -pipe -march=pentiumpro
> Note that '-march=pentiumpro' comes from setting 'CPUTYPE=i686' in
> /etc/make.conf (examples in /usr/share/examples/etc/make.conf).

        Martin Tournoij pointed out what (fine-print) I didn't see
        [never read/very seldom read] that the world and kernel should be
        left at O, O2 or their default.  I signal to gcc to unroll loops
        and know that the compiler writers are going to use their 
        learned and practical wisdom regarding loop unrolling... .

> HTH,

        It has and thanks much.  Gotta rebuild, but no big deal!


> Karol
> -- 
> Karol Kwiatkowski   <karol.kwiat at gmail dot com>
> OpenPGP 0x06E09309

  Gary Kline  [EMAIL PROTECTED]   www.thought.org  Public Service Unix

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