Date: Fri, 19 Mar 2010 11:36:15 -0700 From: Julian Elischer <julian@elischer.org> To: John Baldwin <jhb@freebsd.org> Cc: d@delphij.net, freebsd-arch@freebsd.org Subject: Re: [PATCH] Utilize i686, SSE and MMX by default on FreeBSD/i386 Message-ID: <4BA3C41F.3000404@elischer.org> In-Reply-To: <201003190751.26767.jhb@freebsd.org> References: <4BA2CE17.2050105@delphij.net> <201003190751.26767.jhb@freebsd.org>
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John Baldwin wrote: > On Thursday 18 March 2010 9:06:31 pm Xin LI wrote: >> Hi, >> >> I think it doesn't really make sense to by default use MACHINE_CPU=i486 >> when the kernel is built with SSE by default today. >> >> Attached patch uses i686 SSE MMX by default, the user can always change >> the default setting by overriding CPUTYPE (they have to do it as SSE is >> enabled by default for several years). > > The kernel is only built with support for userland applications using SSE, it > does not _use_ SSE. Similarly, the kernel is built with support for PG_NX > provided on 64-bit processors, but it does not do so by failing to support > older 32-bit processors. I think this change is premature. Users can already > set CPUTYPE in make.conf. Also, most modern x86 server-class machines are > 64-bit in which case they would be running FreeBSD/amd64 and using SSE > already. > and a lot of low power boxes (e.g. soekris) are 586 class.
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