From owner-freebsd-arch Thu May 18 23: 5:12 2000 Delivered-To: freebsd-arch@freebsd.org Received: from obie.softweyr.com (obie.softweyr.com [204.68.178.33]) by hub.freebsd.org (Postfix) with ESMTP id B1BF937BA3C for ; Thu, 18 May 2000 23:05:09 -0700 (PDT) (envelope-from wes@softweyr.com) Received: from softweyr.com (homer.softweyr.com [204.68.178.39]) by obie.softweyr.com (8.8.8/8.8.8) with ESMTP id AAA17630; Fri, 19 May 2000 00:04:54 -0600 (MDT) (envelope-from wes@softweyr.com) Message-ID: <3924DA18.392990EA@softweyr.com> Date: Fri, 19 May 2000 00:07:20 -0600 From: Wes Peters Organization: Softweyr LLC X-Mailer: Mozilla 4.7 [en] (X11; U; FreeBSD 4.0-STABLE i386) X-Accept-Language: en MIME-Version: 1.0 To: Terry Lambert Cc: Chuck Paterson , Doug Rabson , arch@FreeBSD.ORG Subject: Re: Sparc & api for asynchronous task execution (2) References: <200005182045.NAA21595@usr08.primenet.com> 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. -- "Where am I, and what am I doing in this handbasket?" Wes Peters Softweyr LLC wes@softweyr.com http://softweyr.com/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-arch" in the body of the message