From owner-freebsd-hackers Thu May 20 17:26:24 1999 Delivered-To: freebsd-hackers@freebsd.org Received: from dingo.cdrom.com (dingo.cdrom.com [204.216.28.145]) by hub.freebsd.org (Postfix) with ESMTP id 0EB7214E6C for ; Thu, 20 May 1999 17:26:14 -0700 (PDT) (envelope-from mike@dingo.cdrom.com) Received: from dingo.cdrom.com (localhost.cdrom.com [127.0.0.1]) by dingo.cdrom.com (8.9.3/8.8.8) with ESMTP id RAA01979; Thu, 20 May 1999 17:15:51 -0700 (PDT) (envelope-from mike@dingo.cdrom.com) Message-Id: <199905210015.RAA01979@dingo.cdrom.com> X-Mailer: exmh version 2.0.2 2/24/98 To: Joel Ray Holveck Cc: Doug Rabson , Peter Wemm , Tommy Hallgren , freebsd-hackers@FreeBSD.ORG Subject: Re: Lazy SPLs In-reply-to: Your message of "20 May 1999 19:17:42 CDT." <86wvy3wa1l.fsf@detlev.UUCP> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Date: Thu, 20 May 1999 17:15:51 -0700 From: Mike Smith Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG > >>> "Lazy SPLs - The kernel no longer masks hardware events unless a > >>> hardware event actually occurs, avoiding many expensive > >>> operations." > >> We've been doing it for as long as I can remember, at least as far > >> back as 2.0.5, probably as far back as 1.x. > > My earliest memory of it was as "Bruce's new interrupt code" for 386bsd. > > It was part of the 386bsd patchkit I think. > > Why mask out the interrupts at all, instead of queuing them in handler > level? Level-triggered interrupts are persistent conditions, not queueable events. They typically require device-driver level intervention to be cleared. This is a major error in the PCI design (no surprises there). -- \\ The mind's the standard \\ Mike Smith \\ of the man. \\ msmith@freebsd.org \\ -- Joseph Merrick \\ msmith@cdrom.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message