From: David Mosberger <davidm@napali.hpl.hp.com>
To: linux-ia64@vger.kernel.org
Subject: Re: Timer updates revision 7 (asm sets predicates/various fixes)
Date: Mon, 02 Aug 2004 09:36:17 +0000 [thread overview]
Message-ID: <16654.2833.511956.400488@napali.hpl.hp.com> (raw)
In-Reply-To: <Pine.LNX.4.58.0407292044500.3633@schroedinger.engr.sgi.com>
>>>>> On Fri, 30 Jul 2004 08:34:56 -0700 (PDT), Christoph Lameter <clameter@sgi.com> said:
>> The numbers above indicate a substantial slowdown going from 1 to
>> 2 cpus. What happens at higher cpu counts.
Christoph> The code that uses cmpxchg will always be a scalability
Christoph> issue.
Also, you need to keep things in perspective: the test programs
_continually_ bangs on gettimeofday(). If the cmpxchg were a
scalability issue for, say, 16-32-way machines with _real_ workloads,
I'd really be surprised. Now if you have 128 or more CPUs, I do agree
that the picture would be very different and scalability is a much
bigger concern.
--david
next prev parent reply other threads:[~2004-08-02 9:36 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-07-30 3:52 Timer updates revision 7 (asm sets predicates/various fixes) Christoph Lameter
2004-07-30 4:23 ` David Mosberger
2004-07-30 14:45 ` Jack Steiner
2004-07-30 15:30 ` Christoph Lameter
2004-07-30 15:34 ` Christoph Lameter
2004-08-02 9:32 ` David Mosberger
2004-08-02 9:36 ` David Mosberger [this message]
2004-08-03 2:33 ` christoph
2004-08-03 18:06 ` David Mosberger
2004-08-03 21:06 ` Christoph Lameter
2004-08-04 8:31 ` David Mosberger
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