From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kurt Fitzner Subject: Re: [parisc-linux] B132L outperforms C160 - 64-bit userland needed? Date: Tue, 16 Aug 2005 18:03:35 -0600 Message-ID: <43027ED7.10007@excelcia.org> References: <4301B090.9040405@excelcia.org> <200508160800.29307.mszick@morethan.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 To: parisc-linux@lists.parisc-linux.org Return-Path: In-reply-to: <200508160800.29307.mszick@morethan.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 Michael S. Zick wrote: >>When that produced even worse results, I tried -march=2.0 vs 1.1 and >>-mschedule=8000 vs 7300 seperately. Each one alone slows down the >>benchmark and the effect is addititive. It seems that in Linux, right >>now at least, compiling with -march=2.0 or -mschedule=8000 is a Bad Thing. >> > > It would be interesting to see if this also holds with a newer GCC. > (3.4, 4.0, 4.1) I can't see how it would be different. Isn't compiling for PA2.0/8000 in Linux tying of GCC's hands behind its back. You're telling it you want good code for a 64-bit CPU, but it can't produce 64-bit code. Is there any real possibility that this is compiler-related and not simply a 32 vs. 64 bit issue? If there is a real chance of this, I'll bite the bullet and actually test out newer GCC versions. > Try the same version kernel on both machines - you might just be seeing > the difference between 2.6.8 and 2.6.10. (or 32bit and 64bit kernels). I've installed 2.6.8.1 on the C160 to match the B132L. I'm seeing a 2% increase in speed across the board with the different kernel. I attribute this to my having set the CPU to 7300 in the kernel settings. The speed increase is exactly consistent with the difference I see in executables on my C160 when compiled with -march1.1/-mschedule=7300 rather than 2.0/8000. The C160 still underperforms significantly when compared to the B132L. I have not yet compiled a 64-bit kernel for my C160. All advice I have read is that this is a complete waste of time since without a 64-bit userland it will just make the kernel bigger and slower. Is there likely to be any benefit at all to a 64-bit kernel? > Also, what compiler was used to build the kernel. Same as used to build nBench, gcc 3.3.5 (Debian 1:3.3.5-13). Kurt. _______________________________________________ parisc-linux mailing list parisc-linux@lists.parisc-linux.org http://lists.parisc-linux.org/mailman/listinfo/parisc-linux