This message generated a parse failure. Raw output follows here. Please use 'back' to navigate. From devnull@lkml.org Wed Jun 5 14:19:23 2024 Received: from spaans.ds9a.nl (adsl-xs4all.ds9a.nl [213.84.159.51]) by kylie.puddingonline.com (8.11.6/8.11.6) with SMTP id g8IJpxX06052 for ; Wed, 18 Sep 2002 21:52:00 +0200 Received: (qmail 17092 invoked from network); 18 Sep 2002 07:44:42 -0000 Received: from unknown (HELO spaans.ds9a.nl) (3ffe:8280:10:360:202:44ff:fe2a:a1dd) by mayo.ipv6.ds9a.nl with SMTP; 18 Sep 2002 07:44:42 -0000 Received: (qmail 32452 invoked by uid 1000); 17 Sep 2002 21:21:48 -0000 Received: (maildatabase); juh Received: (qmail 16029 invoked by alias); 6 Mar 2002 16:10:12 -0000 Received: (qmail 16017 invoked from network); 6 Mar 2002 16:10:12 -0000 Received: from unknown (HELO dipsaus.ds9a.tudelft.nl) (::ffff:10.0.0.202) by spaans.ds9a.nl with SMTP; 6 Mar 2002 16:10:12 -0000 Received: (qmail 17309 invoked from network); 6 Mar 2002 16:10:12 -0000 Received: from unknown (HELO vger.kernel.org) (::ffff:12.107.208.194) by adsl-xs4all.ds9a.nl with SMTP; 6 Mar 2002 16:10:12 -0000 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Wed, 6 Mar 2002 11:08:13 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Wed, 6 Mar 2002 11:08:04 -0500 Received: from zcars0m9.nortelnetworks.com ([47.129.242.157]:61108 "EHLO zcars0m9.ca.nortel.com") by vger.kernel.org with ESMTP id ; Wed, 6 Mar 2002 11:07:54 -0500 Received: from zcars04f.ca.nortel.com (zcars04f.ca.nortel.com [47.129.242.57]) by zcars0m9.ca.nortel.com (Switch-2.2.0/Switch-2.2.0) with ESMTP id g26G7k128352; Wed, 6 Mar 2002 11:07:46 -0500 (EST) Received: from zcard015.ca.nortel.com (zcard015.ca.nortel.com [47.129.30.7]) by zcars04f.ca.nortel.com (Switch-2.2.0/Switch-2.2.0) with ESMTP id g26G7dG24309; Wed, 6 Mar 2002 11:07:44 -0500 (EST) Received: from zcard0k6.ca.nortel.com ([47.129.242.158]) by zcard015.ca.nortel.com with SMTP (Microsoft Exchange Internet Mail Service Version 5.5.2653.13) id GNHN86H2; Wed, 6 Mar 2002 11:07:40 -0500 Received: from pcard0ks.ca.nortel.com ([47.129.117.131]) by zcard0k6.ca.nortel.com with SMTP (Microsoft Exchange Internet Mail Service Version 5.5.2653.13) id FQT68BLB; Wed, 6 Mar 2002 11:07:39 -0500 Received: from nortelnetworks.com (localhost.localdomain [127.0.0.1]) by pcard0ks.ca.nortel.com (Postfix) with ESMTP id B5AD553EF; Wed, 6 Mar 2002 11:16:08 -0500 (EST) Message-Id: <3C8640C8.367A30BB@nortelnetworks.com> Date: Wed, 06 Mar 2002 11:16:08 -0500 X-Sybari-Space: 00000000 00000000 00000000 From: Chris Friesen X-Mailer: Mozilla 4.77 [en] (X11; U; Linux 2.4.18 i686) X-Accept-Language: en Mime-Version: 1.0 To: Ben Greear Cc: linux-kernel Subject: Re: a faster way to gettimeofday? References: <3C859007.50102@candelatech.com> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org X-Spam-Status: No, hits=0.0 required=5.0 tests=SUBJ_ENDS_IN_Q_MARK version=2.11 Lines: 53 Ben Greear wrote: > > I have a program that I very often need to calculate the current > time, with milisecond accuracy. I've been using gettimeofday(), > but gprof shows it's taking a significant (10% or so) amount of > time. Is there a faster (and perhaps less portable?) way to get > the time information on x86? My program runs as root, so should > have any permissions it needs to use some backdoor hack if that > helps! #include /* get this value from the "cpu MHz" line of /proc/cpuinfo */ #define CLOCKSPEED xxxxxxxx int main() { unsigned int lowbegin, lowend, highbegin, highend; unsigned long long diff; double elapsed; rdtsc(lowbegin,highbegin); //do stuff rdtsc(lowend,highend); if (lowend < lowbegin) highend--; diff = (((unsigned long long) highend - highbegin) << 32) + (lowend - lowbegin); elapsed = (double) diff / CLOCKSPEED; /* elapsed now has time in microseconds, do whatever you wantwith it */ return 0; } -- Chris Friesen | MailStop: 043/33/F10 Nortel Networks | work: (613) 765-0557 3500 Carling Avenue | fax: (613) 765-2986 Nepean, ON K2H 8E9 Canada | email: cfriesen@nortelnetworks.com - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/