From: George Anzinger <george@mvista.com>
To: Abhishek Rai <abba@fsl.cs.sunysb.edu>
Cc: linux-kernel@vger.kernel.org
Subject: Re: rtc_gettimeofday VS. do_gettimeofday
Date: Thu, 11 Mar 2004 13:54:08 -0800 [thread overview]
Message-ID: <4050E000.4030802@mvista.com> (raw)
In-Reply-To: <Pine.LNX.4.44.0403061024150.15658-100000@filer.fsl.cs.sunysb.edu>
Abhishek Rai wrote:
> Hi,
> I need a mechanism to get accurate timeofday from inside the kernel.
> Though rtc_gettimeofday() and do_gettimeofday() both look appropriate, is
> there a reason to prefer one over the other ?
Well, gettimeofday is corrected by ntp, if that matters. It also has a
resolution down to the micro second.
The rtc, on the other hand, is an I/O device (i.e. slower) and only goes to the
second.
If all you need is second resolution the faster way is to use the seconds part
of xtime. This is available as CURRENT_TIME which is defined in
include/linux/sched.h.
--
George Anzinger george@mvista.com
High-res-timers: http://sourceforge.net/projects/high-res-timers/
Preemption patch: http://www.kernel.org/pub/linux/kernel/people/rml
prev parent reply other threads:[~2004-03-11 21:54 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-03-06 15:27 rtc_gettimeofday VS. do_gettimeofday Abhishek Rai
2004-03-11 21:54 ` George Anzinger [this message]
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