Date: Tue, 10 Feb 2004 14:38:11 -0800 From: Kris Kennaway <kris@obsecurity.org> To: Roop Nanuwa <roop@hqst.com> Cc: questions@FreeBSD.org Subject: Re: How about them optimizations? Message-ID: <20040210223810.GA42056@xor.obsecurity.org> In-Reply-To: <40293BB6.5060005@hqst.com> References: <40293BB6.5060005@hqst.com>
next in thread | previous in thread | raw e-mail | index | archive | help
--9jxsPFA5p3P2qPhR Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Feb 10, 2004 at 12:14:46PM -0800, Roop Nanuwa wrote: > Part of my current /etc/make.conf on my 5.2-CURRENT box looks like: >=20 > CPUTYPE=3D athlon-xp > CFLAGS=3D -O2 -pipe -fomit-frame-pointer -mmmx -msse -m3dnow -mfpmath=3Ds= se > COPTFLAGS=3D -O -pipe >=20 > Now what I'm wondering is if those extras like mmmx msse actually do=20 > anything. The > only reason they're in there is because I saw them on a website about=20 > what people > use to optimize gentoo. I had nothing better to do so I recompiled the=20 > world with > them. I didn't really notice anything good or bad happening after that.= =20 > I did have > to mess around with a couple of makefiles to get around the=20 > strict-aliasing problem > that O2 introduces. Besides that, though, are there any advantages or=20 > disadvantages > to compiling with those optimizations and switches? >=20 > Does -mfpmath=3Dsse actually do anything relevent for the FreeBSD world? = I=20 > know > what the GCC manual says about it but I'd rather hear some real world inf= o. >=20 > An enquiring mind wants to know. That's superfluous, because gcc already uses all available opcodes when you tell it to optimize for your CPU type with CPUTYPE=3Dathlon-xp. Using -O2 is recommended against, though - see the sample make.conf file. Kris --9jxsPFA5p3P2qPhR Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.4 (FreeBSD) iD8DBQFAKV1SWry0BWjoQKURAq3vAJ4+QNVcX8shBTojIK6bKYozInvl9wCdFcMx ov0d+TCu+1p1xBtCaaWTLKo= =4EWQ -----END PGP SIGNATURE----- --9jxsPFA5p3P2qPhR--
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20040210223810.GA42056>