From: Mike Kravetz <mkravetz@sequent.com>
To: Sasha Pachev <sasha@mysql.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: Strange thread behaviour on 8-way x86 machine
Date: Tue, 3 Jul 2001 11:51:39 -0700 [thread overview]
Message-ID: <20010703115139.B1128@w-mikek2.des.beaverton.ibm.com> (raw)
In-Reply-To: <0107031225120K.18621@mysql>
In-Reply-To: <0107031225120K.18621@mysql>; from sasha@mysql.com on Tue, Jul 03, 2001 at 12:25:12PM -0600
On Tue, Jul 03, 2001 at 12:25:12PM -0600, Sasha Pachev wrote:
> Hi,
>
> I have observed a rather strange behaviour doing a multi-threaded CPU
> benchmark on an 8-way machine running 2.4.2 SMP kernel. Even when the
> priority is reniced to the highest possible value, I am still unable to reach
> more than 50% CPU utilization. My benchmark just creates a bunch of threads
> with pthread_create(), and then runs a simple integer computation in each
> thread. On a dual with 2.4.3 kernel, and a 4-way with 2.4.2 kernel, I am able
> to reach full CPU utilization.
I haven't had any problem fully utilizing 8 CPUs on 2.4.* kernels. This
may seem obvious, but do you have more than 4 CPUs worth of work for the
system to do? What is the runqueue length during this benchmark?
--
Mike Kravetz mkravetz@sequent.com
IBM Linux Technology Center
next prev parent reply other threads:[~2001-07-03 18:52 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-07-03 18:25 Strange thread behaviour on 8-way x86 machine Sasha Pachev
2001-07-03 18:51 ` Mike Kravetz [this message]
2001-07-06 18:45 ` Sasha Pachev
2001-07-06 19:24 ` Rik van Riel
2001-07-06 20:35 ` Sasha Pachev
2001-07-06 20:41 ` Rik van Riel
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