From owner-freebsd-smp Wed Jan 15 09:02:05 1997 Return-Path: Received: (from root@localhost) by freefall.freebsd.org (8.8.4/8.8.4) id JAA11055 for smp-outgoing; Wed, 15 Jan 1997 09:02:05 -0800 (PST) Received: from clem.systemsix.com (clem.systemsix.com [198.99.86.131]) by freefall.freebsd.org (8.8.4/8.8.4) with SMTP id JAA11048 for ; Wed, 15 Jan 1997 09:02:00 -0800 (PST) Received: from localhost (localhost [127.0.0.1]) by clem.systemsix.com (8.6.12/8.6.12) with SMTP id KAA04351; Wed, 15 Jan 1997 10:00:45 -0700 Message-Id: <199701151700.KAA04351@clem.systemsix.com> X-Authentication-Warning: clem.systemsix.com: Host localhost didn't use HELO protocol X-Mailer: exmh version 1.6.5 12/11/95 From: Steve Passe To: Rob Schofield cc: freebsd-smp@freebsd.org Subject: Re: Motherboard & ChipSet pointers? In-reply-to: Your message of "Wed, 15 Jan 1997 12:57:01 +0700." <199701151157.MAA00873@mccomm.nl> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Date: Wed, 15 Jan 1997 10:00:45 -0700 Sender: owner-smp@freebsd.org X-Loop: FreeBSD.org Precedence: bulk > > EISA should be avoided for SMP/technical reasons (which I have gone into > > in detail in the past). I highly recommend the Gigabyte GA586DX if > > you want a P5 system. P6 is an unknown to me. > > Steve, can you briefly re-hash these for me, or point me at a doc I > can look at? This is worrying as I have picked up an EISA-based server > expressly to run BSD! > > Any info gratefully received. Some EISA systems do not connect the system clock (8254) to the IO APIC.This requires "mixed-mode" programming the IO APIC AND the 8259 ICU. I have already written the code to do this and it appears to work. BUT this is a small in-efficiency for hard-clock INTs. So far ALL EISA systems I have seen use the ISA INTs 0-15 redirection capability for routing both EISA AND PCI INTs to the lower 16 ISA INT vectors. some (majority, but NOT all) PCI/ISA systems route the PCI INTs to upper (ie above 16) IO APIC INTs, thus giving you 4 or more extra INT vectors, helping greatly with the typical "not enough INT choices" on the ISA bus. this fact is the major reason I have for avoiding EISA boards. you need to go thru the mptable database to see details about what I am talking about here. -- Steve Passe | powered by smp@csn.net | FreeBSD -----BEGIN PGP PUBLIC KEY BLOCK----- Version: 2.6.2 mQCNAzHe7tEAAAEEAM274wAEEdP+grIrV6UtBt54FB5ufifFRA5ujzflrvlF8aoE 04it5BsUPFi3jJLfvOQeydbegexspPXL6kUejYt2OeptHuroIVW5+y2M2naTwqtX WVGeBP6s2q/fPPAS+g+sNZCpVBTbuinKa/C4Q6HJ++M9AyzIq5EuvO0a8Rr9AAUR tBlTdGV2ZSBQYXNzZSA8c21wQGNzbi5uZXQ+ =ds99 -----END PGP PUBLIC KEY BLOCK-----