From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Mosberger Date: Fri, 24 Oct 2003 18:36:08 +0000 Subject: Re: Itanium2@900MHz slower than alpha@666MHz ? Message-Id: List-Id: References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-ia64@vger.kernel.org >>>>> On Fri, 24 Oct 2003 10:10:44 -0700, Stephane Eranian said: Stephane> Ionut, On Fri, Oct 24, 2003 at 06:26:55PM +0200, Ionut Stephane> Georgescu wrote: >> Yes, it is a 1.5MB cache CPU. >> But it might be more than just cache misses. When running with a >> 256x256 grid, I am actually using 3 256x257 matrices, which is >> slightly over 1.5MB. I just made a comparison with a 32x32 grid >> and the difference is the same: alpha 10.294s, zx2000 14.777s >> . -O3 is only by 0.4s faster than -O2 in this case. Stephane> Another thing to check is the syslog. Check to see if your Stephane> program is not getting "floating point software assist" Stephane> fault. That can slow you down significantly. Note that on Red Hat you'd have to raise the dmesg level above WARNING to see such messages (dmesg -n8 should do the trick). --david