Date: Tue, 24 Feb 2004 07:25:33 +0700 From: Alain Fauconnet <alain@ait.ac.th> To: Oliver Lehmann <lehmann@ans-netz.de> Cc: freebsd-alpha@freebsd.org Subject: Re: Bad performance on alpha? (make buildworld) Message-ID: <20040224002533.GA9677@ait.ac.th> In-Reply-To: <20040223192103.59ad7b69.lehmann@ans-netz.de> References: <20040223192103.59ad7b69.lehmann@ans-netz.de>
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On Mon, Feb 23, 2004 at 07:21:03PM +0100, Oliver Lehmann wrote: > Hi, > > I run several buildworld's on both, an Alpha EV56 and a Intel PII. I'm > wondering that the Pentium beats the Alpha. Both systems have INVARIANTS* > and WITNESS* disabled. Furthermore, no special tweakups - nearly "out of > the box" configured. > (rest deleted) Just a wild guess: I happen to have had the luck of counting one of the very few guys outside of the US involved in the development of the Alpha chip among my friends. I remember the long fascinating talks we were having when Alpha came out (touch of nostalgia here ;-) and him explaining to me how difficult it was to write a good compiler for the beast. The optimization pass is a real nightmare. At that time we were talking about the EV4 chip, I can only imagine that things have gone worse with the newer generation chips supporting more parallelism, deeper prefetch, branch prediction and all that. So I'm not overly surprised that a job made almost entirely of compiles takes a significant longer time, even though the CPU is more powerful. Now I'll let it to the really knowledgeable persons to give better reasons ;-) Greets, _Alain_
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