Date: Wed, 31 May 2000 20:36:28 -0700 (PDT) From: Matthew Jacob <mjacob@feral.com> To: Terry Lambert <tlambert@primenet.com> Cc: Wes Peters <wes@softweyr.com>, Chuck Paterson <cp@bsdi.com>, Doug Rabson <dfr@nlsystems.com>, arch@FreeBSD.ORG Subject: Re: Sparc & api for asynchronous task execution (2) Message-ID: <Pine.BSF.4.05.10005312026450.477-100000@semuta.feral.com> In-Reply-To: <200005232330.QAA01056@usr05.primenet.com>
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This is a late response on this (I was away for three weeks), but I can report some historical context on sparc register windows and performance issues with them- in going to the DKI/DDI in the SVr4 port, adding the up-tree/down-tree calls for all the DDI calls cost, initially, a 20% performance hit because we really started overflowing windows substantially more with deeper call stacks than had been there in SunOS 4.0. This made the DKI/DDI extremely unpopular within Sun (for obvious reasons other than rules are annoying). I believe that compilers have gotten substantially better since then so I think that this is much less of an issue than it used to be. There are also some other tricks that can make life easier to manage window spills/unspills. The orig SPARC architecture specified a maximum of 32 windows. I don't believe any chips were done deeper than 8- which certainly was and is too small. -matt To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-arch" in the body of the message
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