Date: Thu, 19 Jul 2001 11:59:43 -0700 (PDT) From: John Baldwin <jhb@FreeBSD.ORG> To: Matthew Jacob <mjacob@feral.com> Cc: alpha@FreeBSD.ORG Subject: RE: multiple cpus on an 8200... Message-ID: <XFMail.010719115943.jhb@FreeBSD.org> In-Reply-To: <Pine.BSF.4.21.0107181718220.52716-100000@beppo>
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On 19-Jul-01 Matthew Jacob wrote: > > I got multiple CPUs to appear to be available on an 8200... > > 1. I had to fake past the 'processor available' bit- it wasn't set for the > second CPU even though SRM said it was present and availabele... Yuck. > 2. I came up, and it released it: > > release_aps: releasing secondary CPUs > SMP: AP CPU #9 Launched! > > and I got to a login prompt... but very strangely the system locks up briefly > and then runs okay again. It's quite bizaare. One has to wonder whether or > not > there are some implicit assumptions in the code in places about CPUId. > > It also might in fact be an efficiency issue. We're using PAL calls for > interprocessor interrupts. That *might* be less efficient than using some h/w > specific mechanisms for IPIs. Oh- actually, now that I think about it- I > might > not have enabled IPIs for the CPUs, which means, heh, that IPIs might only be > sampled. Yick... I'll go check... If IPI's are sampled, then that would explain the hang, as the vm system uses rendezvous to invalidate mappings, and in a rendezvous we wait for all CPU's to ack the rendezvous before performing the action and returning. I assume you mean enabling IPI's in a hardware specific sense in SRM or some such? > -matt -- John Baldwin <jhb@FreeBSD.org> -- http://www.FreeBSD.org/~jhb/ PGP Key: http://www.Baldwin.cx/~john/pgpkey.asc "Power Users Use the Power to Serve!" - http://www.FreeBSD.org/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-alpha" in the body of the message
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