Date: Fri, 10 Nov 2006 17:09:11 -0500 From: Michael Proto <mproto@secureworks.com> To: "Jason C. Wells" <jcw@highperformance.net> Cc: freebsd-stable <freebsd-stable@freebsd.org> Subject: Re: Compiler Options Message-ID: <4554F887.5000806@secureworks.com> In-Reply-To: <4554D43E.5010700@highperformance.net> References: <4554D43E.5010700@highperformance.net>
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>From /usr/src/sys/conf/kern.mk: # On the i386, do not align the stack to 16-byte boundaries. Otherwise GCC # 2.95 adds code to the entry and exit point of every function to align the # stack to 16-byte boundaries -- thus wasting approximately 12 bytes of stack # per function call. While the 16-byte alignment may benefit micro benchmarks, # it is probably an overall loss as it makes the code bigger (less efficient # use of code cache tag lines) and uses more stack (less efficient use of data # cache tag lines). Explicitly prohibit the use of SSE and other SIMD # operations inside the kernel itself. These operations are exclusively # reserved for user applications. # .if ${MACHINE_ARCH} == "i386" && ${CC} != "icc" CFLAGS+= -mno-align-long-strings -mpreferred-stack-boundary=2 \ -mno-mmx -mno-3dnow -mno-sse -mno-sse2 INLINE_LIMIT?= 8000 .endif -Proto Jason C. Wells wrote: > I have set CPUTYPE=p3 in make.conf. When I compile my kernel I see > -march=pentium3 as I expect. I also see -mno-mmx and -mno-sse are set > which I do not expect given that -march=pentium3 is used. I presume > that I want MMX and SSE since my processor supports it. What options do > I set and where do I set them to get a kernel properly tuned for pentium3? > > Thanks, > Jason C. Wells > _______________________________________________ > freebsd-stable@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-stable > To unsubscribe, send any mail to "freebsd-stable-unsubscribe@freebsd.org" -- Michael Proto | SecureWorks Unix Administrator | PGP ID: 5D575BBE | mproto@secureworks.com *******************************************************
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