From: Nicholas Mc Guire <der.herr@hofr.at>
To: Jan Kiszka <jan.kiszka@web.de>
Cc: Armin Steinhoff <armin@steinhoff.de>,
Monica Puig-Pey <puigpeym@unican.es>,
linux-rt-users@vger.kernel.org
Subject: Re: I/O operations priority in RTOS
Date: Mon, 6 Jun 2011 02:21:42 +0200 [thread overview]
Message-ID: <20110606002142.GA32539@opentech.at> (raw)
In-Reply-To: <4DEC0A7F.7090207@web.de>
>
> There are good examples - in the RT domain - for both models. Sharing a
> device does not necessarily mean making things dynamic or even
> unpredictable.
>
then I maybe dont get the "exclusive" issue you note - if the highest priority task does not have exclusive access - assuming that there is not contention free sharing - how can you give guarantees ? I can imagin sharing if the highest priority has unconstraint access to the reource and any other access is controled by the highest priority task (i.e. queue replication like ARINC 653 queueing ports) but if you have multiple instances of different priority accessing a resource I don't see how this could be done while giving guarantees on timing (assuming that it is not possible to provide all access as physically atomic instructions)
Do you have an example at hand of such a shared I/O device scheme that can guarantee rt timing ?
> >
> > Any pointers to VFIO ?
>
> E.g. http://thread.gmane.org/gmane.linux.kernel.pci/10088
>
thanks.
hofrat
next prev parent reply other threads:[~2011-06-06 0:21 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-06-04 11:48 One Interrupted Threads per Interrupt line? Monica Puig-Pey
2011-06-04 12:03 ` I/O operations priority in RTOS Monica Puig-Pey
2011-06-04 12:30 ` kernel threads in drivers using the RT patch Monica Puig-Pey
2011-06-06 11:47 ` Changing Kernel thread priorities Monica Puig-Pey
2011-06-06 11:54 ` Rolando Martins
2011-06-06 11:58 ` Monica Puig-Pey
2011-06-06 16:49 ` Mark Hounschell
2011-06-07 8:40 ` Monica Puig-Pey
2011-06-07 9:14 ` Mark Hounschell
2011-06-07 9:46 ` Mark Hounschell
2011-06-07 18:34 ` Monica Puig-Pey
2011-06-07 18:55 ` Mark Hounschell
2011-06-10 10:12 ` Monica Puig-Pey
2011-06-06 18:20 ` Armin Steinhoff
2011-06-04 23:42 ` I/O operations priority in RTOS Nicholas Mc Guire
2011-06-05 8:46 ` Armin Steinhoff
2011-06-05 9:25 ` Jan Kiszka
2011-06-05 22:39 ` Armin Steinhoff
2011-06-05 23:09 ` Jan Kiszka
2011-06-05 9:28 ` Nicholas Mc Guire
2011-06-05 9:44 ` Jan Kiszka
2011-06-05 22:29 ` Nicholas Mc Guire
2011-06-05 23:00 ` Jan Kiszka
2011-06-06 0:21 ` Nicholas Mc Guire [this message]
2011-06-06 20:35 ` Jan Kiszka
2011-06-06 7:41 ` Armin Steinhoff
2011-06-06 20:48 ` Jan Kiszka
2011-06-05 22:32 ` Armin Steinhoff
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