Date: Sat, 4 Mar 2017 10:52:46 -0500 From: Pedro Giffuni <pfg@FreeBSD.org> To: Slawa Olhovchenkov <slw@zxy.spb.ru> Cc: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: Re: svn commit: r314669 - head/sys/i386/conf Message-ID: <ef83ffe1-6198-3468-d132-849c5d38f52d@apache.org> In-Reply-To: <20170304153228.GM15630@zxy.spb.ru> References: <201703041504.v24F4HMh023937@repo.freebsd.org> <20170304153228.GM15630@zxy.spb.ru>
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On 03/04/17 10:32, Slawa Olhovchenkov wrote: > On Sat, Mar 04, 2017 at 03:04:17PM +0000, Pedro F. Giffuni wrote: > >> Author: pfg >> Date: Sat Mar 4 15:04:17 2017 >> New Revision: 314669 >> URL: https://svnweb.freebsd.org/changeset/base/314669 >> >> Log: >> Drop i486 from the default i386 GENERIC kernel configuration. >> >> 80486 production was stopped by Intel on September 2007. Dropping the 486 >> configuration option from the GENERIC kernel improves performance >> slightly. >> >> Removing I486_CPU is consistent at this time: we don't support any >> processor without a FPU and the PC-98 arch, which frequently involved i486 >> CPUs, is also gone so we don't test such platforms anymore. > > What is realy mean? This means we don't do work-arounds that would be required for raw 486. Instead we will use the 586 instructions by default. > Some Via CPU is like i486 (by instruction set). > > CPU: VIA Ezra (800.04-MHz 686-class CPU) > Origin="CentaurHauls" Id=0x678 Family=0x6 Model=0x7 Stepping=8 > Features=0x803035<FPU,DE,TSC,MSR,MTRR,PGE,MMX> > AMD Features=0x80000000<3DNow!> > 486 never had MMX extensions. This is a 686, performance should improve ~4%. Pedro.
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