From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Sharp Subject: Re: [parisc-linux] B132L outperforms C160 - 64-bit userland needed? Date: Wed, 17 Aug 2005 12:40:58 -0700 Message-ID: <20050817194058.GA3378@netfall.com> References: <4301B090.9040405@excelcia.org> <20050817061913.GA8761@colo.lackof.org> <430384FE.6080105@excelcia.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii To: parisc-linux@lists.parisc-linux.org Return-Path: In-Reply-To: <430384FE.6080105@excelcia.org> List-Id: parisc-linux developers list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: parisc-linux-bounces@lists.parisc-linux.org On Wed, Aug 17, 2005 at 12:42:06PM -0600, Kurt Fitzner wrote: > Grant Grundler wrote: > > > If performance on a C160 is that important, my advice is to dump > > both boxes and buy any Pentium M (1.x Ghz) laptop :^). But that would > > be boring... :^P > > Boring indeed. :) > > Actually, my thought is that my little C160 may be simply shedding light > on a problem that's more global. The C160 is the slowest PA2.0 machine > made. It's one of the few machines where a PA2.0 CPU is in the same > speed range as PA1.1 CPUs. It seems like you're answering your own question here. I'm an hppa-ignoramus, but the thing that sticks out the most of all this is that the machines aren't that different in clock rate, but are that different in cache size. So stop ignoring that difference. Cache thrashing is a real, and sad, international problem. Take those benchmarks that produce slower results on a P4/2MB cache processor than they do on a P4/512KB processor. Same motherboard, OS, benchmark. Only difference, 4x bigger cache. If the processor is spending more time loading cache lines, it's spending less time computating. Cache systems are designed to improve the performance of general computing tasks, and many benchmarks fall outside that realm. What's interesting is that some processors have caches so big that these benchmarks do still fit inside them (8MB, 16MB, etc) and those processors look really good on those benchmarks (pucker up your lips and say "SPEC"), compared to cheaper, but really much faster, processors. And as for the gcc compiler switch differences, it seems that maybe the 3.3.5 or whatever just isn't that great when it comes to 2.0/8000 optimizations. Not really a shocker, but good to know, as it makes the case for taking a similar look at 4.0 and 4.1 performance. Mayhaps there is still time to put some changes into gcc 4.x before a final version is nailed down for etch or ? I must be getting bored by pentiums. What's an old, dual processor parisc/2.0 machine go for on ebay these days? ~:^) a _______________________________________________ parisc-linux mailing list parisc-linux@lists.parisc-linux.org http://lists.parisc-linux.org/mailman/listinfo/parisc-linux