Date: Wed, 25 Feb 2004 10:28:13 -0800 From: "David O'Brien" <obrien@freebsd.org> To: Brooks Davis <brooks@one-eyed-alien.net> Cc: "'freebsd-amd64@FreeBSD.org'" <freebsd-amd64@freebsd.org> Subject: Re: Performance comparison, ULE vs 4BSD and AMD64 vs i386 Message-ID: <20040225182813.GE7567@dragon.nuxi.com> In-Reply-To: <20040224215847.GC6356@Odin.AC.HMC.Edu> References: <1077658664.92943.15.camel@.rochester.rr.com> <20040224215847.GC6356@Odin.AC.HMC.Edu>
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On Tue, Feb 24, 2004 at 01:58:47PM -0800, Brooks Davis wrote: > > How about AMD64 being slower than i386 on the same hardware? By > > slower, I mean a buildworld -j4 took about 400 seconds longer in AMD64 > > mode. > > You can't usefully compare compile times when you are compiling for > a different instructions set. The work involved is rairly the same > so the results are meaning less. If you could factor out the cost of > building the native bootstrap tools since that isn't the same job on > each machine, the speed of a cross buildworld would be an intresting > test. For comparing i386 and amd64, I'd probably build an alpha or > sparc64 world so the target would be entierly different. While generally true (everyone used to compare i386 & Alpha); the 80% of the amd64 instruction set is the i386 instruction set, and most of the code generation code is shared between the two. -- -- David (obrien@FreeBSD.org)
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