Date: Mon, 13 Sep 2004 16:12:59 -0500 From: Puna Tannehill <puna@imagescape.com> To: "Conrad J. Sabatier" <conrads@cox.net> Cc: freebsd-questions@freebsd.org Subject: Re: 3dnow, mmx, k6-2 optimizing? Message-ID: <41460D5B.3030100@imagescape.com> In-Reply-To: <20040913141026.6d572ae2@dolphin.local.net> References: <4145D786.4080807@imagescape.com> <20040913141026.6d572ae2@dolphin.local.net>
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Conrad J. Sabatier wrote: > On Mon, 13 Sep 2004 12:23:18 -0500, Puna Tannehill <puna@imagescape.com> > wrote: > > >>I've been looking for possible flags, optimizations, really anything >>that would help me setup my laptop to use mmx and 3dnow. I've updated >> >>/etc/make.conf to -march to the drum of a k6-2, but I'm not even sure >>if mmx and 3dnow are being taken into consideration for compiling and >>such, especially for Xorg. >> >>I did some googling and found people who used CFLAGS like -mmmx and >>-m3dnow, but when I run with those options, they fail and said to be >>invalid. they don't appear in 'man gcc' which should have been the >>first place i looked. I'm not finding anything in terms of compiling >>or configuring Xorg to use 3dnow or mmx, or even how to check to see >>if they are automatically detected and used. >> >>Any thoughts? >> >>Puna > > > I don't know why those flags would not be working for you; I've been > using them for quite some time now on my Athlon (32-bit) box. One > oddity I just noticed very recently is that, with the recent patches to > "make", the CPUTYPE variable seems to be ignored now, which is why I > explicitly added the "-march" flag to CFLAGS. Also, note that I don't > use "-mmmx -m3dnow" for kernel builds; you don't want to be doing this, > as it can easily break things in the kernel, but for general builds > and port builds, it's fine: > > CPUTYPE?=athlon I had that problem too. The '?=' should be just '='. I see in the notes that '?=' is for compiling for different machine, but I don't do that so I just left is as 'CPUTYPE=' and it added the -march accordingly. > CFLAGS= -O3 -pipe -march=athlon -mmmx -m3dnow > > # buildkernel variables settings > > KERNCONF=CUSTOM > COPTFLAGS= -O3 -pipe -march=athlon I see many people using a -O3, but I've never been able to use any optimization levels above -O without compile errors, or having problems with SSH. Just out of curiosity, do you see a significant different in performance with that level of optimization? Puna It's working for me now, I'm not sure why it was failing before. Puna
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