From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Mosberger Date: Thu, 20 Feb 2003 17:52:43 +0000 Subject: Re: [Linux-ia64] strange performance behaviour with floats 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 Thu, 20 Feb 2003 09:35:02 +0100, Volker Birk said: Volker> On Wed, Feb 19, 2003 at 11:09:36AM -0800, David Mosberger Volker> wrote: Hello, I'm wondering about the strange behaviour of Volker> the Linux scheduling on my rx5670: >> Can you reproduce the behavior with a standard 2.4.xx ia64 kernel >> (not with Red Hat's heavily patched kernel)? Volker> That is a standard 2.4.xx ia64 kernel (with ia64 patches Volker> from kernel.org). Volker> bronto:~ # uname -a Linux bronto 2.4.19 #11 SMP Sat Nov 2 Volker> 18:47:02 CET 2002 ia64 GNU/Linux bronto:~ # Hmmh, that's really strange. I assume you realize that your test-program doesn't really do what the source code suggests (the loop-body gets optimized away), but regardless the high variation you're seeing seems wrong. Are you re-directing the kernel console to a serial line? If so, make sure there is no logging activity when the program runs slower (especially a slow baud-rate can "stall" the kernel for non-trivial amounts of time). --david