From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jon Smirl Subject: Re: Interrupt forwarding Date: Sat, 12 Mar 2005 13:53:58 -0500 Message-ID: <9e4733910503121053773b5f70@mail.gmail.com> References: <9e47339105031210332d8756f0@mail.gmail.com> Reply-To: Jon Smirl Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit In-Reply-To: Sender: xen-devel-admin@lists.sourceforge.net Errors-To: xen-devel-admin@lists.sourceforge.net List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , List-Archive: To: Keir Fraser Cc: xen-devel@lists.sourceforge.net, Ian Pratt , ian.pratt@cl.cam.ac.uk List-Id: xen-devel@lists.xenproject.org On Sat, 12 Mar 2005 18:48:53 +0000, Keir Fraser wrote: > > On 12 Mar 2005, at 18:33, Jon Smirl wrote: > > >> Shared interrupts are slightly worse because the irq won't get > >> unmasked > >> until all receivers say their work is done. If one lock sup it starves > >> the rest -- until this is detected and that domain gets blown away. > > > > After you blow away the domain how do you acknowledge the interrupt? > > Is all hardware required to have a tiny driver in the supervisor to > > handling acking in this case? If you don't ack it, it is going to keep > > interrupting. > > We don't go that far. A sensible approach would be to require the > driver to be restarted, and to reset the hardware device, before > unmasking. Or to rate limit each interrupt line to an > administrator-configurable 'reasonable' number of IRQs per second -- > this might also catch bugs where drivers are not properly acking > devices for other reasons. In x86 boxes almost everything is shared. Leaving the interrupt masked off will probably disable 20% of the hardware in the box. -- Jon Smirl jonsmirl@gmail.com ------------------------------------------------------- SF email is sponsored by - The IT Product Guide Read honest & candid reviews on hundreds of IT Products from real users. Discover which products truly live up to the hype. Start reading now. http://ads.osdn.com/?ad_id=6595&alloc_id=14396&op=click