From owner-freebsd-smp Wed Apr 19 18:40:17 2000 Delivered-To: freebsd-smp@freebsd.org Received: from TYO203.gate.nec.co.jp (TYO203.gate.nec.co.jp [202.32.8.211]) by hub.freebsd.org (Postfix) with ESMTP id 5923B37B7E2 for ; Wed, 19 Apr 2000 18:40:14 -0700 (PDT) (envelope-from mihara@prd.fc.nec.co.jp) Received: from mailsv.nec.co.jp (mailsv-le1 [192.168.1.90]) by TYO203.gate.nec.co.jp (8.9.3/3.7W00031314) with ESMTP id KAA05091; Thu, 20 Apr 2000 10:40:13 +0900 (JST) Received: from elmer.prd.fc.nec.co.jp (root@elmer.prd.fc.nec.co.jp [10.32.193.1]) by mailsv.nec.co.jp (8.9.3/3.7W-MAILSV-NEC) with ESMTP id KAA14980; Thu, 20 Apr 2000 10:40:11 +0900 (JST) Received: from oz.prd.fc.nec.co.jp (oz.prd.fc.nec.co.jp [10.32.193.3]) by elmer.prd.fc.nec.co.jp (8.8.8/3.6W-00032121) with ESMTP id KAA14655; Thu, 20 Apr 2000 10:40:08 +0900 (JST) Date: Thu, 20 Apr 2000 10:39:47 +0900 Message-ID: <868zy9v9cs.wl@oz.prd.fc.nec.co.jp> From: Osamu MIHARA To: gallatin@cs.duke.edu Cc: freebsd-smp@freebsd.org Subject: Re: I/O APIC In-Reply-To: In your message of "Wed, 19 Apr 2000 17:56:01 -0400 (EDT)" <14590.10426.763064.533504@grasshopper.cs.duke.edu> References: <14590.10426.763064.533504@grasshopper.cs.duke.edu> User-Agent: Wanderlust/1.1.0 (Overjoyed) SEMI/1.13.7 (Awazu) FLIM/1.13.2 (Kasanui) MULE XEmacs/21.1 (patch 9) (Canyonlands) (i386-unknown-freebsd3.4) Organization: NEC Corporation, Tokyo Japan MIME-Version: 1.0 (generated by SEMI 1.13.7 - "Awazu") Content-Type: text/plain; charset=US-ASCII Sender: owner-freebsd-smp@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org # I just started to study APIC and SMP stuffs, so please correct me if # I'm wrong. At Wed, 19 Apr 2000 17:56:01 -0400 (EDT), Andrew Gallatin wrote: > 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? One advantage is that multiple I/O-APICs can handle more interrupts than traditional PIC. If you use PIC, it can handles only 16 interrupts at most, and you may need share a interrupt for some devices. With multiple IO-APICs, you don't need to share interrupts, and it does not pay for overheads of interrupt sharing, resulting in better I/O throughput, even with single CPU. -- Osamu MIHARA // NEC Printers Division To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-smp" in the body of the message