From owner-freebsd-arch Tue Apr 11 9:59:49 2000 Delivered-To: freebsd-arch@freebsd.org Received: from ns1.yes.no (ns1.yes.no [195.204.136.10]) by hub.freebsd.org (Postfix) with ESMTP id 05F6937BB05 for ; Tue, 11 Apr 2000 09:59:36 -0700 (PDT) (envelope-from eivind@bitbox.follo.net) Received: from bitbox.follo.net (bitbox.follo.net [195.204.143.218]) by ns1.yes.no (8.9.3/8.9.3) with ESMTP id SAA16089 for ; Tue, 11 Apr 2000 18:59:38 +0200 (CEST) Received: (from eivind@localhost) by bitbox.follo.net (8.8.8/8.8.6) id SAA08251 for freebsd-arch@freebsd.org; Tue, 11 Apr 2000 18:59:33 +0200 (CEST) Received: from feral.com (feral.com [192.67.166.1]) by hub.freebsd.org (Postfix) with ESMTP id 6BB0237BAE8 for ; Tue, 11 Apr 2000 09:59:25 -0700 (PDT) (envelope-from mjacob@feral.com) Received: from semuta.feral.com (semuta [192.67.166.70]) by feral.com (8.9.3/8.9.3) with ESMTP id JAA24591; Tue, 11 Apr 2000 09:58:54 -0700 Date: Tue, 11 Apr 2000 09:59:00 -0700 (PDT) From: Matthew Jacob Reply-To: mjacob@feral.com To: Terry Lambert Cc: arch@freebsd.org Subject: Re: BUF/BIO roadmap. In-Reply-To: <200004111649.JAA17290@usr01.primenet.com> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-arch@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG > > It also seems to me that kernel threads are _still_ a significantly > bad idea, since the problems faced in kernel preemption are a subset > of the problems faced in Real Time support, and that as a result, it > will be significantly harder to support Hard Real Time in the future > without significant revisions of the the OS architecture. Whether it's threads or additional kernel processes that can be schedule from interrupt level, I don't care, but the class of problems this solves for me makes it very desirable. The current approach in Linux of creating an interrupt/error handler thread per SCSI host adapter is *very* cool with respect to solving complex error issues in a clean fashion. The existing CAM subsystem would be a *lot* easier to follow/debug if it were threads/proc based. From a political point of view it's important as well. Veritas points out to me that they'll be porting VxFS and other products to Linux long before they'd port it to FreeBSD because Linux (like Solaris, NT, HP/UX) have a kernel threads model. You may be right with what you assert- I won't attempt to involve myself at that level, but from the point of view of this platform succeeding, well, I believe you're lifting at the heavy end, my friend. -matt To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-arch" in the body of the message