From: David Mosberger <davidm@napali.hpl.hp.com>
To: linux-ia64@vger.kernel.org
Subject: Re: Itanium2@900MHz slower than alpha@666MHz ?
Date: Fri, 24 Oct 2003 18:36:08 +0000 [thread overview]
Message-ID: <marc-linux-ia64-106702084805517@msgid-missing> (raw)
In-Reply-To: <marc-linux-ia64-106700871121653@msgid-missing>
>>>>> On Fri, 24 Oct 2003 10:10:44 -0700, Stephane Eranian <eranian@hpl.hp.com> 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
next prev parent reply other threads:[~2003-10-24 18:36 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
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 [this message]
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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