From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matthew Wilcox Date: Fri, 24 Oct 2003 16:49:29 +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, Oct 24, 2003 at 06:26:55PM +0200, Ionut 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. > > The variations are within +-0.02s between runs (for the 32x32 case). > > Is there a way to test the bandwidth of the cache ? Because I think the > alphas have actually 2MB of L2 cache, not L3. I don't know about testing cache bandwidth, but /proc/pal/cpu0/cache_info gives various stats on how the different levels of cache play together on ia64. -- "It's not Hollywood. War is real, war is primarily not about defeat or victory, it is about death. I've seen thousands and thousands of dead bodies. Do you think I want to have an academic debate on this subject?" -- Robert Fisk