From owner-freebsd-smp Wed Apr 19 14:57:15 2000 Delivered-To: freebsd-smp@freebsd.org Received: from duke.cs.duke.edu (duke.cs.duke.edu [152.3.140.1]) by hub.freebsd.org (Postfix) with ESMTP id 296C337BCA6 for ; Wed, 19 Apr 2000 14:56:03 -0700 (PDT) (envelope-from gallatin@cs.duke.edu) Received: from grasshopper.cs.duke.edu (grasshopper.cs.duke.edu [152.3.145.30]) by duke.cs.duke.edu (8.9.3/8.9.3) with ESMTP id RAA04071 for ; Wed, 19 Apr 2000 17:56:02 -0400 (EDT) Received: (from gallatin@localhost) by grasshopper.cs.duke.edu (8.9.3/8.9.1) id RAA02765; Wed, 19 Apr 2000 17:56:02 -0400 (EDT) (envelope-from gallatin@cs.duke.edu) From: Andrew Gallatin MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Date: Wed, 19 Apr 2000 17:56:01 -0400 (EDT) To: freebsd-smp@freebsd.org Subject: I/O APIC X-Mailer: VM 6.43 under 20.4 "Emerald" XEmacs Lucid Message-ID: <14590.10426.763064.533504@grasshopper.cs.duke.edu> Sender: owner-freebsd-smp@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org This is probably a dumb question, so forgive me. My low-level system knowledge is pretty much limited to alphas & I don't know a lot about PCs. When installing Solaris/x86 on one of our PowerEdge 2400s (SMP capable, 2 I/O APICs, 1 CPU), I noticed that it uses the I/O APICs for interrupts rather than the normal isa irq x. Is there an advantage to this? This rang a bell, because the same PowerEdge2400 tends to spew 'stray irq 15' when under heavy interrupt load & running FreeBSD. There's nothing attached to irq 15. I'm thinking that the traditional irq method is probably not well tested on this hardware since it would seem that at least some OSes use the I/O APIC even in single CPU mode. Would it be better for FreeBSD run I/O APIC capable machines via the I/O APIC even when using only a single CPU? I know we can't do this now, but would it be worth sorting through that code? Is there more to it than untangling the IOAPIC and SMP ifdefs? Again, apologies for the dumb question. ------------------------------------------------------------------------------ Andrew Gallatin, Sr Systems Programmer http://www.cs.duke.edu/~gallatin Duke University Email: gallatin@cs.duke.edu Department of Computer Science Phone: (919) 660-6590 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-smp" in the body of the message