Date: Tue, 14 Feb 2006 10:51:22 -0500 From: Vinny Abello <vinny@tellurian.com> To: freebsd-stable@FreeBSD.ORG Subject: Re: clock reverts to epoch on boot? Message-ID: <7.0.1.0.2.20060214104201.0845a270@tellurian.com> In-Reply-To: <200602140945.k1E9jxBa048710@lurza.secnetix.de> References: <7.0.1.0.2.20060213212221.04c7da20@tellurian.com> <200602140945.k1E9jxBa048710@lurza.secnetix.de>
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At 04:45 AM 2/14/2006, Oliver Fromme wrote: >Vinny Abello <vinny@tellurian.com> wrote: > > CPUTYPE=pentium4 > >Better use "?=". Yes, I saw that error and corrected it. Thanks. That wasn't the source of my problems actually, but I at least have it specified properly now. > > CFLAGS= -O2 -pipe > > COPTFLAGS= -O -pipe > >I recommend not to overide those two at all. Especially >your CFLAGS setting might generate broken code because >there are sources which are not aliasing-clean, which can >break with any optimizations beyond -O, unless you also >specify -fno-strict-aliasing. Really? Are there any current examples of such? I've never run into this myself, but I'm sure you wouldn't be recommending it if it wasn't true. What about -funroll-loops and -ffast-math? I see a lot of people using those options in general as well. I actually found one reference from someone claiming -O3 is good in CFLAGS and -O2 for COPTFLAGS although I have read a lot of things about why not to use -O3 in CFLAGS and that it's not supported at all with buildworld, so I'm not really interested in using that at all, even with ports. >The defaults are "-O2 -fno-strict-aliasing -pipe" for >CFLAGS, and for COPTFLAGS it's "-O -pipe" if DEBUG is >defined (the default in GENERIC), otherwise "-O2 -pipe >-fno-strict-aliasing". Is -O2 safe on COPTFLAGS if you have debugging disabled in the KERNCONF? I usually disable it as I have no interest in debugging the kernel (nor have I had problems where I've needed to... yet). I've found references in the archives that it is desirable to get (keep?) the kernel working with -O2 optimizations. Any pointers appreciated. TIA! Vinny Abello Network Engineer Server Management vinny@tellurian.com (973)300-9211 x 125 (973)940-6125 (Direct) PGP Key Fingerprint: 3BC5 9A48 FC78 03D3 82E0 E935 5325 FBCB 0100 977A Tellurian Networks - The Ultimate Internet Connection http://www.tellurian.com (888)TELLURIAN "Courage is resistance to fear, mastery of fear - not absence of fear" -- Mark Twain
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