Date: Tue, 2 Mar 2004 12:25:24 -0500 From: John Baldwin <jhb@FreeBSD.org> To: smp@FreeBSD.org Cc: freebsd-smp@freebsd.org Subject: Re: Parallel interrupt threads Message-ID: <200403021225.24472.jhb@FreeBSD.org> In-Reply-To: <4044B412.4E604099@syskonnect.de> References: <4044B412.4E604099@syskonnect.de>
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On Tuesday 02 March 2004 11:19 am, Gerald Heinig wrote: > Hello all, > > I have a question about the assumptions I can make when designing the > locking scheme for my driver. > I need to know whether more than one interrupt thread can execute at any > time for a particular device. Under some systems (eg. Aix, I believe) > one can specify whether the interrupt service routine should be called > sequentially or whether it can be called in parallel on multiple > processors. In other words, do I need to lock (portions of) the ISR > against itself, or is there a guarantee that at most one ISR will be > active for a given device at any time? > > Also, what about processor binding? IIRC Solaris can bind all interrupts > from a particular device to one CPU. Does FreeBSD do this too, or can > any CPU process the ISR? Not that it matters which CPU actually does the > work, but it's an extension to the question above. > > Any answers much appreciated. Currently only a single ISR will execute at a time and I don't expect that to change any time soon. Ithreads currently are not bound to CPUs but execute on any CPU. -- John Baldwin <jhb@FreeBSD.org> <>< http://www.FreeBSD.org/~jhb/ "Power Users Use the Power to Serve" = http://www.FreeBSD.org
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