content-class: urn:content-classes:message
Subject: RE: timing an application
Date: Tue, 14 Jan 2003 12:37:05 -0800
Message-ID: <331AD7BED1579543AD146F5A1A44D525127AD6@fmsmsx403.fm.intel.com>
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From: "Howell, David P" <david.p.howell@intel.com>
To: "Maciej Soltysiak" <solt@dns.toxicfilms.tv>,
       <linux-kernel@vger.kernel.org>
Sender: linux-kernel-owner@vger.kernel.org

If this is on a IA32(Pentium II or later)/IA64 have you considered using
the processor TSC register to get interval timestamps? It's a lot
lighter weight and should give better resolution. When we have done this
we compared the tick values directly.

To convert TSC ticks to time the /proc/cpuinfo value for 'cpu MHz', see
the glibc get_clockfreq.c and hp_timing.h implementation for details.

Dave Howell

-----Original Message-----
From: Maciej Soltysiak [mailto:solt@dns.toxicfilms.tv] 
Sent: Tuesday, January 14, 2003 2:58 PM
To: linux-kernel@vger.kernel.org
Subject: timing an application

Hi,

being inspired by some book about optimizing c++ code i decided to do
timing of functions i wrote. I am using gettimeofday to set
two timeval structs and calculate the time between them.
But the results depend heavily on the load, also i reckon that this
is an innacurate timing.

Any ideas on timing a function, or a block of code? Maybe some kernel
timers or something.

Regards,
Maciej Soltysiak

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