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From: George Anzinger <george@mvista.com>
To: Chris Friesen <cfriesen@nortel.com>
Cc: Nishanth Aravamudan <nacc@us.ibm.com>,
	john stultz <johnstul@us.ibm.com>, Liu Qi <liuqi@ict.ac.cn>,
	"'high-res-timers-discourse@lists.sourceforge.net'" 
	<high-res-timers-discourse@lists.sourceforge.net>,
	Darren Hart <dvhltc@us.ibm.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: Help with the high res timers
Date: Wed, 04 May 2005 13:31:48 -0700	[thread overview]
Message-ID: <42793134.7000407@mvista.com> (raw)
In-Reply-To: <42790A18.4000008@nortel.com>

Chris Friesen wrote:
> George Anzinger wrote:
> 
>> The, I think, elegant solution to the timer storm problem is to not 
>> restart the timer until the user picks up the prior expiration.  This 
>> dynamically adjusts the timer response to the amount of machine 
>> available at the time.
> 
> 
> The disadvantage is that you then lose accuracy since each timer 
> interval is increased by some random amount based on system scheduling. 
>  What about some kind of ulimit-type thing to specify the minimum 
> recurring interval that can be specified?  If root so specifies, you 
> could have 1usec interval timers and the system would hang.  This is 
> conceptually no different than busy-looping in a SCHED_FIFO task.

The standard comes to the rescue here.  The standard defines timer_getoverrun() 
which returns the number of additional timeouts you _would_ have seen if you had 
been fast enough.

I tried a limit thing.  It is MUCH too fragile for the real world.
> 
-- 
George Anzinger   george@mvista.com
High-res-timers:  http://sourceforge.net/projects/high-res-timers/

  parent reply	other threads:[~2005-05-04 20:36 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <E1DSl7F-0002v2-Ck@sc8-sf-web4.sourceforge.net>
     [not found] ` <20050503024336.GA4023@ict.ac.cn>
     [not found]   ` <4277EEF7.8010609@mvista.com>
     [not found]     ` <1115158804.13738.56.camel@cog.beaverton.ibm.com>
     [not found]       ` <427805F8.7000309@mvista.com>
     [not found]         ` <20050504001307.GF3372@us.ibm.com>
2005-05-04 17:10           ` Help with the high res timers George Anzinger
2005-05-04 17:44             ` Chris Friesen
2005-05-04 17:51               ` Nishanth Aravamudan
2005-05-04 18:16                 ` Chris Friesen
2005-05-04 20:36                   ` George Anzinger
2005-05-04 20:31               ` George Anzinger [this message]
2005-05-04 18:14             ` Darren Hart
2005-05-04 21:46               ` George Anzinger
     [not found]         ` <1115166592.13738.96.camel@cog.beaverton.ibm.com>
2005-05-04 17:46           ` George Anzinger
2005-05-04 22:13             ` john stultz
2005-05-04 22:48               ` George Anzinger
2005-05-04 23:27                 ` john stultz

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