From owner-freebsd-arch Fri May 19 10:44:48 2000 Delivered-To: freebsd-arch@freebsd.org Received: from smtp02.primenet.com (smtp02.primenet.com [206.165.6.132]) by hub.freebsd.org (Postfix) with ESMTP id DDFEC37BDFE for ; Fri, 19 May 2000 10:44:45 -0700 (PDT) (envelope-from tlambert@usr02.primenet.com) Received: (from daemon@localhost) by smtp02.primenet.com (8.9.3/8.9.3) id KAA19479; Fri, 19 May 2000 10:44:42 -0700 (MST) Received: from usr02.primenet.com(206.165.6.202) via SMTP by smtp02.primenet.com, id smtpdAAAK7aG7L; Fri May 19 10:44:32 2000 Received: (from tlambert@localhost) by usr02.primenet.com (8.8.5/8.8.5) id KAA00232; Fri, 19 May 2000 10:44:28 -0700 (MST) From: Terry Lambert Message-Id: <200005191744.KAA00232@usr02.primenet.com> Subject: Re: Sparc & api for asynchronous task execution (2) To: wes@softweyr.com (Wes Peters) Date: Fri, 19 May 2000 17:44:27 +0000 (GMT) Cc: tlambert@primenet.com (Terry Lambert), cp@bsdi.com (Chuck Paterson), dfr@nlsystems.com (Doug Rabson), arch@FreeBSD.ORG In-Reply-To: <3924DA18.392990EA@softweyr.com> from "Wes Peters" at May 19, 2000 12:07:20 AM X-Mailer: ELM [version 2.5 PL2] MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: owner-freebsd-arch@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG > Terry Lambert wrote: > > > > > }I didn't realize that every function call involved a fault on the sparc > > > }architecture - that sounds pretty nasty. > > > > > > Actually every function call doesn't cause a fault, every > > > time you overflow/underflow the current set of register windows causes a > > > fault. (Perhaps what you meant). This means that calling a function > > > from the bottom most function will cause two faults, one for going down > > > and one eventually as you go up. > > > > > > This makes going up and down when you don't overflow > > > very fast at the expense of when you add to the total depth. > > The register window sizes weren't picked willy-nilly. The SPARC default > size is 7 windows, chosen after months of analyzing every M68K SunOS > program they could get their hands, including compiled C, Pascal, LISP, > and Fortran programs. > > I suspect C++ and Java probably skew these stats a little. This might > account for the 8 windows in more modern SPARC processors. Please watch your attributions; I said none of this. The truncated pat that included my comments was merely a reference to the 1991 University of Washington paper on SPARC register windows and user space threading, which has a good discussion of SPARC register windows. PS: Not to give you a hard time, but this stuff is archived, and I am always prepared to defend/acknowledge-incorrectness for everything I say, but not for what others say. 8-). Terry Lambert terry@lambert.org --- Any opinions in this posting are my own and not those of my present or previous employers. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-arch" in the body of the message