From owner-freebsd-smp Thu Jun 22 14: 1:38 2000 Delivered-To: freebsd-smp@freebsd.org Received: from sydney.worldwide.lemis.com (pm236.conference.usenix.org [209.179.127.236]) by hub.freebsd.org (Postfix) with ESMTP id 38C1337B6BF for ; Thu, 22 Jun 2000 14:01:34 -0700 (PDT) (envelope-from grog@sydney.worldwide.lemis.com) Received: (from grog@localhost) by sydney.worldwide.lemis.com (8.9.3/8.9.3) id OAA01038; Thu, 22 Jun 2000 14:01:07 -0700 (PDT) (envelope-from grog) Date: Thu, 22 Jun 2000 14:01:07 -0700 From: Greg Lehey To: Matthew Dillon Cc: Nick Hibma , freebsd-smp@FreeBSD.ORG Subject: Re: irunning, width in bits. Message-ID: <20000622140107.E845@sydney.worldwide.lemis.com> References: <200006211539.IAA94918@apollo.backplane.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Mailer: Mutt 1.0pre2i In-Reply-To: <200006211539.IAA94918@apollo.backplane.com> Organization: LEMIS, PO Box 460, Echunga SA 5153, Australia Phone: +61-8-8388-8286 Fax: +61-8-8388-8725 Mobile: +61-418-838-708 WWW-Home-Page: http://www.lemis.com/~grog X-PGP-Fingerprint: 6B 7B C3 8C 61 CD 54 AF 13 24 52 F8 6D A4 95 EF Sender: owner-freebsd-smp@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org On Wednesday, 21 June 2000 at 8:39:02 -0700, Matthew Dillon wrote: > (Moving this to freebsd-smp, Bcc'ing current) > >> What about shared interrupts? How are they going to be treated? With the >> spl leaving the arena it somehow looks feasible to run one interrupt >> source on two different threads if there are two pieces of hardware >> attached to the same interrupt line. >> >>> From what I understood from dfr, when switching away from an interrupt >> handler it is converted into a full thread. When the second piece of >> hardware fires an interrupt it could then run at the same time. > > This came up at the meeting and the conclusion was that shared > interrupts would run serially. That is, each 'bit' in the cpl > (spl*(), also represented by ipending, the vector table > dispatch, and so forth) would be treated as a single interrupt > thread. If there are N interrupts hanging off that IRQ, then > each of the N would be run serially from a single interrupt > thread. I think, however, that Nick's suggestion is a thing we should follow up on--*after* we have got the simple case working. Once we have the ability to block in interrupt context, I'm sure we'll find lots of applications for our new-found freedom, some of them good. But first we need to understand the environment. Greg -- Finger grog@lemis.com for PGP public key See complete headers for address and phone numbers To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-smp" in the body of the message