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From: George Anzinger <george@mvista.com>
To: Chris Friesen <cfriesen@nortelnetworks.com>
Cc: "Perez-Gonzalez, Inaky" <inaky.perez-gonzalez@intel.com>,
	root@chaos.analogic.com, "Brown, Len" <len.brown@intel.com>,
	Tim Schmielau <tim@physik3.uni-rostock.de>,
	john stultz <johnstul@us.ibm.com>,
	lkml <linux-kernel@vger.kernel.org>
Subject: Re: gradual timeofday overhaul
Date: Mon, 25 Oct 2004 16:12:06 -0700	[thread overview]
Message-ID: <417D8846.3090308@mvista.com> (raw)
In-Reply-To: <41783AE7.8040705@nortelnetworks.com>

Chris Friesen wrote:
> George Anzinger wrote:
> 
>> Well, that is part of the accounting overhead the increases with 
>> context switch rate.  You also need to include the time it takes to 
>> figure out which of the time limits is closes (run time limit, profile 
>> time, slice time, etc).  Then, you also need to remove the timer when 
>> switching away.  No, it is not a lot, but it is way more than the 
>> nothing we do when we can turn it all over to the periodic tick.  The 
>> choice is load sensitive overhead vs flat overhead.
> 
> 
> It should be possible to be clever about this.  Most processes don't use 
> their timeslice, so if we have a previous timer running, just keep track 
> of how much beyond that timer our timeslice will be.  If we context 
> switch before the timer expiry, well and good.  If the timer expires, 
> set it for what's left of our timeslice.

Me thinks that rather quickly devolves to a periodic tick.

-- 
George Anzinger   george@mvista.com
High-res-timers:  http://sourceforge.net/projects/high-res-timers/


  reply	other threads:[~2004-10-26  1:25 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-10-21  8:32 Perez-Gonzalez, Inaky
2004-10-21 21:17 ` George Anzinger
2004-10-21 22:40   ` Chris Friesen
2004-10-25 23:12     ` George Anzinger [this message]
2004-10-25 23:51       ` Chris Friesen
  -- strict thread matches above, loose matches on Subject: below --
2004-10-22  0:29 Perez-Gonzalez, Inaky
2004-10-21 21:32 Perez-Gonzalez, Inaky
2004-10-21 22:36 ` Chris Friesen
2004-10-22  0:21 ` George Anzinger
2004-10-19 18:21 process start time set wrongly at boot for kernel 2.6.9 Jerome Borsboom
2004-10-19 20:11 ` john stultz
2004-10-20  0:42   ` Tim Schmielau
2004-10-20  0:59     ` john stultz
2004-10-20  3:05       ` gradual timeofday overhaul Tim Schmielau
2004-10-20  7:47         ` Len Brown
2004-10-20 15:09           ` George Anzinger
2004-10-20 15:59             ` Richard B. Johnson
2004-10-20 15:17           ` George Anzinger
2004-10-20 17:09           ` Lee Revell
2004-10-20 21:42             ` Len Brown
2004-10-20 18:13         ` john stultz

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