Date: Fri, 22 Sep 2000 19:24:30 -0400 From: "Otter" <otterr@telocity.com> To: <freebsd-questions@FreeBSD.ORG> Subject: RE: Intel cpu's and the -march switch Message-ID: <HLEDJBJKDDPDJBMGCLPPOELBCDAA.otterr@telocity.com> In-Reply-To: <20000922095828.A4861@node1.cluster.srrc.usda.gov>
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}-----Original Message----- }From: owner-freebsd-questions@FreeBSD.ORG }[mailto:owner-freebsd-questions@FreeBSD.ORG]On Behalf Of }Glenn Johnson }Sent: Friday, September 22, 2000 10:58 AM }To: S. David Pullara; freebsd-questions@FreeBSD.ORG }Subject: Re: Intel cpu's and the -march switch } } }On Fri, Sep 22, 2000 at 09:56:44AM +0700, John Indra wrote: } }> On Thu, Sep 21, 2000 at 01:44:25PM -0500, Glenn Johnson wrote: }> }> |You will not notice any perceptible performance improvement but }> |you may notice your kernel and/or programs acting strangely after }> |compiling with those options. I would recommend that you }_not_ bother }> |with the -march or -mcpu options. }> }> How strange? } }The keyword was _may_ in "may notice". In any event it has }been stated }very clearly on the mailing lists that if you use optimizations above }the default -O and something is not working correctly that you are on }your own. } }> I've been having this /etc/make.conf entry on my personal }workstation }> since the day FreeBSD 4.1-RELEASE (now, it's FreeBSD }4.1-STABLE) was }> out: }> }> CFLAGS= -O6 -march=pentiumpro -funroll-loops }-fstrength-reduce -ffast-math -fexpensive-optimizations }-fomit-frame-pointer -pipe }> COPTFLAGS= -O6 -march=pentiumpro -funroll-loops }-fstrength-reduce -ffast-math -fexpensive-optimizations }-fomit-frame-pointer -pipe }> CXXFLAGS+= -fmemoize-lookups -fsave-memoized WTF is -O6? i saw -O, -O1, -O2, -O3 and -Os... what do you get from using the 6? I don't see anything in the man page for it. -Otter }> This is not my production machine, only the machine I used }daily as: }> web servers, proxy, firewall&NAT, mail server, DNS, and I }use GIMP and }> XMMS a lot. In working hours, my baby is ``tortured'' really bad, a }> lot of request from approximately 40 other Windows based }PC. It's a }> Compaq Deskpro with Pentium III 500 MHz and 256 MB of RAM. }> }> Days of uptime, without any unintentional reboots, and my feeling }> tells me that with those optimization, my machine runs faster :))) } }The original question was with regards to the -march or -mcpu flags }specifically. You have gone way beyond that in your }optimizations. The }-fomit-frame-pointer flag will definitely give a boost in performance }and should not cause any problems except with debugging. I gave my }recommendation based on the specifics of the question but }after all it }was just a recommendation. } }-- }Glenn Johnson }USDA, ARS, SRRC Phone: (504) 286-4252 }New Orleans, LA 70124 e-mail: gjohnson@nola.srrc.usda.gov } } }To Unsubscribe: send mail to majordomo@FreeBSD.org }with "unsubscribe freebsd-questions" in the body of the message To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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