Date: Thu, 28 Jul 2005 02:13:15 -0700 From: ray@redshift.com To: Erich Dollansky <oceanare@pacific.net.sg> Cc: freebsd-amd64@freebsd.org Subject: Re: Benchmarks: AMD64 vs i386 on Dual 246 Opteron Message-ID: <3.0.1.32.20050728021315.00a4d188@pop.redshift.com> In-Reply-To: <42E89FCF.5070307@pacific.net.sg> References: <3.0.1.32.20050728013152.00a4d188@pop.redshift.com> <3.0.1.32.20050728013152.00a4d188@pop.redshift.com>
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At 05:05 PM 7/28/2005 +0800, Erich Dollansky wrote: | Hi, | | ray@redshift.com wrote: | | > MySQL, re-ran the benchmarks. Much to my surprise, just changing the OS from 64 | > bit to 32 bit caused the machine to double in speed. The results are attached | | I do not wonder at all. | | I did some software development for PA-RISC and SPARC machines. Naiv as | I am, I started with the perfect 64 bit program which resulted in bad | performance. | | I then collected hints of how to mix 8, 16, 32 and 64 bit data to make | the program much faster. The TCP/IP based application run then five | times faster on the same machine compared to the plain 64 bit program. | | 64 bit programs copy to many unused information around. | | It will be very difficult to tune a huge source base to maximum | performance and keep it compatible between 32 and 64 bit. | | The pointers mentioned by you are only a small part of the problem. The | main problem is - at least in my program, and as far as what I saw in | the sources here - the data handling. | | Erich Thank you for the info - that makes sense and certainly backs up what I was seeing as well. Ray
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