From mboxrd@z Thu Jan  1 00:00:00 1970
Subject: Re: [Xenomai-core] [RFC][PATCH 4/4] shorten overrun loops of
	periodic timers
From: Philippe Gerum <rpm@xenomai.org>
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Date: Thu, 03 Aug 2006 19:01:39 +0200
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To: Jan Kiszka <jan.kiszka@domain.hid>
Cc: xenomai-core <xenomai@xenomai.org>

On Thu, 2006-08-03 at 09:01 +0200, Jan Kiszka wrote:
> A simple patch, just like suggested by Gilles, to avoid looping over
> periodic xntimer handlers in case of overruns.
> 
> It saves the current TSC on loop entry and uses this value later when
> forwarding the timer. Is is the overhead of re-reading the TSC on all
> archs negligible and should we rather go that way?
> 

The configuration for which reading the TSC is fairly expensive is x86
+TSC emulation, since this incurs reading and writing a couple of
8254-related i/o ports. This is not an issue for other
archs/x86-configs.

> Jan
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-- 
Philippe.