From owner-freebsd-arch Fri Jan 25 21:37:30 2002 Delivered-To: freebsd-arch@freebsd.org Received: from ns.yogotech.com (ns.yogotech.com [206.127.123.66]) by hub.freebsd.org (Postfix) with ESMTP id 27BA837B41D for ; Fri, 25 Jan 2002 21:37:17 -0800 (PST) Received: from caddis.yogotech.com (caddis.yogotech.com [206.127.123.130]) by ns.yogotech.com (8.9.3/8.9.3) with ESMTP id WAA06425; Fri, 25 Jan 2002 22:36:44 -0700 (MST) (envelope-from nate@yogotech.com) Received: (from nate@localhost) by caddis.yogotech.com (8.11.6/8.11.6) id g0Q5aUD47592; Fri, 25 Jan 2002 22:36:31 -0700 (MST) (envelope-from nate) From: Nate Williams MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <15442.16478.408033.680185@caddis.yogotech.com> Date: Fri, 25 Jan 2002 22:36:30 -0700 To: Terry Lambert Cc: Nate Williams , Daniel Eischen , Dan Eischen , k Macy , Peter Wemm , Julian Elischer , arch@FreeBSD.ORG Subject: Re: KSE question In-Reply-To: <3C51FF0A.9ACAC316@mindspring.com> References: <3C51D0B6.F6E04EBC@mindspring.com> <15441.56832.170618.611705@caddis.yogotech.com> <3C51E888.FD13A18D@mindspring.com> <15441.59691.361172.394760@caddis.yogotech.com> <3C51F18A.C0D8D6B1@mindspring.com> <15441.62092.864056.841853@caddis.yogotech.com> <3C51F492.CB0FB69E@mindspring.com> <15441.62830.180895.121111@caddis.yogotech.com> <3C51F89E.78DAD01D@mindspring.com> <15441.63876.271856.290838@caddis.yogotech.com> <3C51FF0A.9ACAC316@mindspring.com> X-Mailer: VM 6.96 under 21.1 (patch 14) "Cuyahoga Valley" XEmacs Lucid Reply-To: nate@yogotech.com (Nate Williams) Sender: owner-freebsd-arch@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG > > > > Otherwise known as not having a complete solution to the problem, hence > > > > not having a solution at all. :( > > > > > > It maps the problem space, so it's a complete solution. > > > > No, it doesn't. It's a 75% solution, and the remaining 25% is extremely > > common. Not an acceptable solution. > > FPU usage is uncommon. If it were 51% common, we'd just pay > the cost of switching it all the time, and this discussion > would not have started. Depends on what you consider common. I'll bet that a significant percentage of programs use the FPU. However, they use the FPU *very* little in the total amount of time used. So, even if they use it once, that's enough to cause problems if you don't handle it correctly. > > Plus, it's not possible to do, since there are no 'Good' java->native > > code compilers for FreeBSD. (There is only one decent compiler out, and > > it isn't ported to FreeBSD. And, GCC is *NOT* that compiler, as it's > > Java stuff isn't useful for anything real.) > > 8^). We agree on two things, now. 8-) 8-). Wow. Better write it on my calendar. > > > Cool! Let's just dike the thing out! > > > > > > I know, we can compile the FPU emulation library into user > > > space, and not use the hardware FPU at all. Then we can fix > > > the emulated FPU, and the problem goes away. 8-) 8-) 8-). > > > > Yeah, sure. > > How about this: force trigger the exception before context > switching away, if the FPU has been used. Again, the issue is that we can't determine *IF* the FPU has been used effeciently. All solutions assume this solution, although Daniel's may have a way of short-circuiting this in the short term. Nate To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-arch" in the body of the message