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From: Ben Greear <greearb@candelatech.com>
To: Davide Libenzi <davidel@xmailserver.org>
Cc: linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: a faster way to gettimeofday?
Date: Tue, 05 Mar 2002 21:20:25 -0700	[thread overview]
Message-ID: <3C859909.30602@candelatech.com> (raw)
In-Reply-To: <Pine.LNX.4.44.0203051955090.1475-100000@blue1.dev.mcafeelabs.com>



Davide Libenzi wrote:

> On Tue, 5 Mar 2002, 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!
>>
> 
> If you're on x86 you can use collect rdtsc samples and convert them to ms.
> You'll get even more then ms accuracy.


Can I do this from user space?  If so, any examples or docs
you can point me to?

Also, I'm looking primarily for a speed increase, not an accuracy
increase.

Thanks for the response!

Ben


> 
> 
> 
> 
> - Davide
> 
> 
> 
> -
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-- 
Ben Greear <greearb@candelatech.com>       <Ben_Greear AT excite.com>
President of Candela Technologies Inc      http://www.candelatech.com
ScryMUD:  http://scry.wanfear.com     http://scry.wanfear.com/~greear



  reply	other threads:[~2002-03-06  4:20 UTC|newest]

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2002-03-06  3:41 a faster way to gettimeofday? Ben Greear
2002-03-06  3:58 ` Davide Libenzi
2002-03-06  4:20   ` Ben Greear [this message]
2002-03-06  4:31     ` Davide Libenzi
2002-03-06  4:34       ` Davide Libenzi
2002-03-07 14:14       ` a faster way to gettimeofday? rdtsc strangeness Terje Eggestad
2002-03-07 14:41         ` Alan Cox
2002-03-07 15:43           ` Terje Eggestad
2002-03-07 16:17             ` Alan Cox
2002-03-07 18:32             ` H. Peter Anvin
2002-03-08  1:32               ` Jamie Lokier
2002-03-08  1:35                 ` H. Peter Anvin
2002-03-08  1:57                   ` Jamie Lokier
2002-03-08 18:30                     ` gettimeofday() system call timing curiosity Jamie Lokier
2002-03-08 18:50                       ` H. Peter Anvin
2002-03-08 20:16                         ` Jamie Lokier
2002-03-08 20:30                           ` Davide Libenzi
2002-03-08 18:54                       ` Richard B. Johnson
2002-03-08 19:06                         ` johan.adolfsson
2002-03-08 19:16                           ` H. Peter Anvin
2002-03-08 19:45                           ` Richard B. Johnson
2002-03-08 20:29                             ` johan.adolfsson
2002-03-08 20:43                             ` Alan Cox
2002-03-09  3:03                               ` pjd
2002-03-09 18:51                                 ` Alan Cox
2002-03-09  3:15                             ` Kelsey Hudson
2002-03-08 19:19                         ` Alan Cox
2002-03-08 20:40                         ` george anzinger
2002-03-06 20:45     ` a faster way to gettimeofday? dean gaudet
2002-03-06 21:31       ` Chris Ball
2002-03-06 22:25         ` george anzinger
2002-03-07  0:04         ` vsyscalls Mark Mielke
2002-03-06 16:16 ` a faster way to gettimeofday? Chris Friesen
2002-03-06 16:54   ` Richard B. Johnson
2002-03-11 22:47 ` OBATA Noboru
2002-03-12 13:06   ` Jamie Lokier
2002-03-12 15:12     ` OBATA Noboru

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