Date: Wed, 28 Jun 2000 23:18:36 +0000 (GMT) From: Terry Lambert <tlambert@primenet.com> To: frank@exit.com Cc: tlambert@primenet.com (Terry Lambert), jasone@canonware.com (Jason Evans), smp@FreeBSD.ORG Subject: Re: SMP meeting summary Message-ID: <200006282318.QAA03832@usr08.primenet.com> In-Reply-To: <200006260631.XAA43949@realtime.exit.com> from "Frank Mayhar" at Jun 25, 2000 11:31:51 PM
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> Terry Lambert wrote: > > In Streams, this was addressed by removing two primitives, and creating > > what are called "priority bands" to deal with the issue (I worked for > > Novell USG when UnixWare was going to 2.0 and integrating the ES/MP code > > into the SVR4 base, and saw much of this happen). > > Speaking of which, there has _got_ to be a better way. It's possible > when dealing with Streams to get into nested-lock situations where you > need a lock with a lower priority and it's not possible (due to constraints > elsewhere) to raise the priority of the lock. And, of course, it's always > dangerous to raise the priority of an existing lock, since you may miss > a case. > > I'm not sure that interrupt threads are the right way to go either, though. > > If there even _is_ a "right" way. One way that was "accidently" discovered at Novell was to run into the streams stack at interrupt context, until one reached a synchronization point. Obviously, this doesn't work the same in all stacks, and can only be run to completion unidirectionally, in the best case, but it was enough to justify the changeover to ODI drivers. 8-). Terry Lambert terry@lambert.org --- Any opinions in this posting are my own and not those of my present or previous employers. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-smp" in the body of the message
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