Date: Wed, 09 Apr 2003 16:53:17 -0700 From: Terry Lambert <tlambert2@mindspring.com> To: John Baldwin <jhb@FreeBSD.org> Cc: freebsd-smp@freebsd.org Subject: Re: System freezes with SMP support enabled Message-ID: <3E94B26D.9C13C13E@mindspring.com> References: <XFMail.20030409120027.jhb@FreeBSD.org>
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John Baldwin wrote: > > Second, it seems to me that there's a possibility for a deadlock > > if an interrupt comes in on one CPU, and an ithread to handle it > > is scheduled to run on a different CPU. You may want to try using > > SCHED_4BSD to see if that changes anything. > > Huh? Where in the code do you see this happening exactly? All the > bits you should need to look at for this are in ithread_schedule() > and ithread_loop() in sys/kern/kern_intr.c. Off-list, I have been helping someone debug an ithread_exit() bug, after which they can submit the patches if they want. I saw that there might be an issue if affinity is applied to ithread scheduling, if the interrupt is not routed to the CPU with the affinity. THis was a side issue, having nothing to do with the problem I was trying to help debug at the time, but it tickled my suspic-o-meter. > Not only that, but 4.8 doesn't have ithreads so I doubt seriously > that this is causing the lockups on 4.x. Yeah, my bad. I was only considering the case of his complaint on 5.0, since he complained about both 5.0 and 4.8, and 5.0 last, so that's what was in my recall buffer. 8-) 8-). -- Terry
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