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From: Chris Friesen <cfriesen@nortelnetworks.com>
To: David Vrabel <dvrabel@arcom.com>
Cc: Linux Kernel <linux-kernel@vger.kernel.org>
Subject: Re: Jiffy based timers/timeouts can expire too soon.
Date: Thu, 02 Dec 2004 10:35:44 -0600	[thread overview]
Message-ID: <41AF4460.2000404@nortelnetworks.com> (raw)
In-Reply-To: <41AF3D50.4090707@arcom.com>

David Vrabel wrote:
> Hi,
> 
> Jiffy based timers and timeouts can expire too soon because the timer 
> interrupt accounts for lost ticks and can increment jiffies by more than 1.

On the other hand, you also need to account for lost ticks for timers that 
started before interrupts were turned off, otherwise they could run for extra time.

It would be nice to have some kind of constant frequency timestamp that 
increments regardless of sleep state or interrupt status, so that sleep periods 
and such are based on timestamps rather than ticks (the period of which can vary).

Chris


  reply	other threads:[~2004-12-02 16:35 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-12-02 16:05 Jiffy based timers/timeouts can expire too soon David Vrabel
2004-12-02 16:35 ` Chris Friesen [this message]
2004-12-02 18:47 ` john stultz
2004-12-02 23:28   ` Anton Blanchard
2004-12-16 20:38     ` George Anzinger

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