Date: Mon, 27 Nov 2000 13:54:08 -0800 From: Alfred Perlstein <bright@wintelcom.net> To: Kenneth Culver <culverk@culverk.student.umd.edu> Cc: freebsd-questions@FreeBSD.ORG Subject: Re: compiler optimizations Message-ID: <20001127135408.P8051@fw.wintelcom.net> In-Reply-To: <Pine.BSF.4.21.0011271644040.2988-100000@culverk.student.umd.edu>; from culverk@culverk.student.umd.edu on Mon, Nov 27, 2000 at 04:46:55PM -0500 References: <Pine.BSF.4.21.0011271644040.2988-100000@culverk.student.umd.edu>
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* Kenneth Culver <culverk@culverk.student.umd.edu> [001127 13:47] wrote: > I'm just curious about something. I noticed the other day that the entire > linux kernel is compiled with options -O2 -m486. I was wondering if this > really causes any performance increase and was also wondering if there is > anywhere on the web that can show this. I am wondering because I was going > to use these options with FreeBSD (or -march=pentiumpro or -mpentiumpro, > and -Os instead of -O2). Yes, the optimization works, however because we still want to support 386s and because of bad experiances with the gcc optimizer in the past we don't really like to debug problems with kernels that have high levels of optimization because sometimes it's gcc's fault (or at least it could be in the past). If you want to compile the kernel and world like that edit /etc/make.conf and add your options to CFLAGS: CFLAGS= -O -pipe -- -Alfred Perlstein - [bright@wintelcom.net|alfred@freebsd.org] "I have the heart of a child; I keep it in a jar on my desk." To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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