From: Matthew Wilcox <willy@debian.org>
To: linux-ia64@vger.kernel.org
Subject: Re: Itanium2@900MHz slower than alpha@666MHz ?
Date: Fri, 24 Oct 2003 16:49:29 +0000 [thread overview]
Message-ID: <marc-linux-ia64-106701452429692@msgid-missing> (raw)
In-Reply-To: <marc-linux-ia64-106700871121653@msgid-missing>
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
next prev parent reply other threads:[~2003-10-24 16:49 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-10-24 15:14 Itanium2@900MHz slower than alpha@666MHz ? Ionut Georgescu
2003-10-24 15:35 ` Matthew Wilcox
2003-10-24 16:26 ` Ionut Georgescu
2003-10-24 16:49 ` Matthew Wilcox [this message]
2003-10-24 16:55 ` Grant Grundler
2003-10-24 17:10 ` Stephane Eranian
2003-10-24 17:42 ` Chen, Kenneth W
2003-10-24 18:36 ` David Mosberger
2003-10-24 18:55 ` Ionut Georgescu
2003-10-24 18:59 ` Ionut Georgescu
2003-10-24 20:25 ` Siddha, Suresh B
2003-10-24 20:36 ` Chen, Kenneth W
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