Date: Mon, 7 Jan 2002 12:13:18 -0500 From: Jake Burkholder <jake@locore.ca> To: Terry Lambert <tlambert2@mindspring.com> Cc: Bernd Walter <ticso@cicely8.cicely.de>, Alfred Perlstein <bright@mu.org>, Dan Eischen <eischen@vigrid.com>, arch@FreeBSD.ORG Subject: Re: Request for review: getcontext, setcontext, etc Message-ID: <20020107121318.G39321@locore.ca> In-Reply-To: <3C396554.9B6A9053@mindspring.com>; from tlambert2@mindspring.com on Mon, Jan 07, 2002 at 01:07:32AM -0800 References: <3C37E559.B011DF29@vigrid.com> <20020106032709.A82406@elvis.mu.org> <3C381B48.AADDCA2B@mindspring.com> <20020106113847.A15885@cicely8.cicely.de> <20020107015228.E39321@locore.ca> <3C396554.9B6A9053@mindspring.com>
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Apparently, On Mon, Jan 07, 2002 at 01:07:32AM -0800, Terry Lambert said words to the effect of; > Jake Burkholder wrote: > > > > > > Is there a reason that getcontext and setcontext need to be > > > > > > system calls? > > > > > Atomicity? > > > > To flush register windows on setcontext() on SPARC. > > > wflush isn't a priviledged instruction and usualy emulated on < sparcv9. > > > mit-pthreads use it from userland. > > > > Yes, this (flushw) is the best way to flush the windows on v9 at least. > > > > > > > > Are there any performance reasons to flush windows in kernel? > > > > No, doing so is actually more complicated (slightly) due to having > > to use copyout and due potentialy having to deal with 32bit applications > > running on 64bit kernels. It is easier if the spills look like normal > > spills. > > The "flushw" is not enough. Actually it is. > > The following paper discusses the original implementation of the > "liblwp" code on SunOS 4.x: > > http://www.cs.washington.edu/research/compiler/papers.d/thread-regwin.html I've read this paper. v9 is quite different than v8. I don't think we'll ever support v8. We do support v9. Have a nice day. Jake To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-arch" in the body of the message
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