Date: Thu, 5 Dec 1996 11:37:58 -0700 (MST) From: Terry Lambert <terry@lambert.org> To: smp@csn.net (Steve Passe) Cc: ccsanady@friley216.res.iastate.edu, peter@spinner.dialix.com, smp@freebsd.org Subject: Re: make locking more generic? Message-ID: <199612051837.LAA19621@phaeton.artisoft.com> In-Reply-To: <199612051723.KAA13519@clem.systemsix.com> from "Steve Passe" at Dec 5, 96 10:23:56 am
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> So whenever a CPU acquires the lock I have > the code set the priority of that CPU to "VERY LOW". So now all pending INTs > will be sent to it, which it can deal with since it already holds the lock. > When a CPU releaes the lock it resets its priority to "NORMAL". > > The problem is that whenever a CPU gets an INT its PPR is increased to > the priority of the INT, thus negating the "VERY LOW" prio I set in the > TPR. So if a CPU is behind the lock because of an INT it WON'T get > sent other pending INTs, the other CPU will. Now that we have IPIs > working I hope to be able to send an IPI to the other CPUs telling them to set > their TPR to "VERY HIGH", thus dis-abling them from getting INTs. I don't understand. If CPU 1 is servicing INT 12 from a disk controller, and you get INT 4 from a serial port, don't you *want* CPU 2 to service the INT 4 in parallel??? Terry Lambert terry@lambert.org --- Any opinions in this posting are my own and not those of my present or previous employers.
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