Date: Sun, 28 Feb 2010 14:39:58 +0000 From: Paul B Mahol <onemda@gmail.com> To: Aaron Lewis <aaron.lewis1989@gmail.com> Cc: freebsd-questions@freebsd.org Subject: Re: Compiler Flags problem with core2 CPU Message-ID: <3a142e751002280639rdb25d3ajd688caecfedfacbb@mail.gmail.com> In-Reply-To: <4B8A7FA7.1070200@gmail.com> References: <4B8A63D5.90104@gmail.com> <3a142e751002280624w6f38d297o65b88301b3e5f8d@mail.gmail.com> <4B8A7FA7.1070200@gmail.com>
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Do not top post. On 2/28/10, Aaron Lewis <aaron.lewis1989@gmail.com> wrote: > Really ? It's bad to use custom flags to compile kernel , why do you > think so ? > I'd like to know more about this : ) Use google. > > So setting optimize compiler flags is only useful for userland stuff ? > > Paul B Mahol wrote: >> On 2/28/10, Aaron Lewis <aaron.lewis1989@gmail.com> wrote: >> >>> Hi, >>> I gonna recompile kernel for my core2 CPU , so i'd like to pass some >>> flags to gcc. >>> Kinds of "-march=core2" , i tried to modify /etc/make.conf >>> >>> e.g CFLAGS += -march=core2 -O20 -ffast-math -mfpmath=sse >>> But it fails .. bad arch switch , core2 cpu is not supported ? >>> >> It is bad idea to compile kernel with custom flags. And gcc in FreeBSD >> doesn't know about core2, >> use 'native' if you must. >> >> >>> And is that useful to let gcc select cpu specified asm code ? >>> >> >> Only for some userland stuff like openssl. >> > > > -- > Best Regards, > Aaron Lewis - PGP: 0xA476D2E9 > irc: A4r0n on freenode > >
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