From owner-freebsd-arch Wed Nov 22 16: 4:23 2000 Delivered-To: freebsd-arch@freebsd.org Received: from pike.osd.bsdi.com (pike.osd.bsdi.com [204.216.28.222]) by hub.freebsd.org (Postfix) with ESMTP id 7CB5A37B4CF for ; Wed, 22 Nov 2000 16:04:19 -0800 (PST) Received: from laptop.baldwin.cx (john@jhb-laptop.osd.bsdi.com [204.216.28.241]) by pike.osd.bsdi.com (8.11.1/8.9.3) with ESMTP id eAN03uW03917; Wed, 22 Nov 2000 16:03:56 -0800 (PST) (envelope-from jhb@FreeBSD.org) Message-ID: X-Mailer: XFMail 1.4.0 on FreeBSD X-Priority: 3 (Normal) Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 8bit MIME-Version: 1.0 In-Reply-To: Date: Wed, 22 Nov 2000 16:04:02 -0800 (PST) From: John Baldwin To: Daniel Eischen Subject: Re: Thread-specific data and KSEs Cc: bright@wintelcom.net, jlemon@flugsvamp.com, arch@FreeBSD.org, Terry Lambert Sender: owner-freebsd-arch@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On 22-Nov-00 Daniel Eischen wrote: > On Wed, 22 Nov 2000, John Baldwin wrote: >> >> On 22-Nov-00 Terry Lambert wrote: >> > The %gs register already has to be saved for WINE processes, >> > so it's taken (at least when USER_LDT is defined). So there >> > would not be an additional context switch for it. >> >> Ok. Since %fs is only used in the kernel and is saved/restored it might be >> a >> good thing to use instead. > > I didn't think %fs was saved, but if it is, that's fine > with me too. Hmm, if it isn't it is trivial to save it. >> > I think that if you guys go forward with this, you should do an >> > indirect through whatever you end up using. I realize this will >> > cost an additional 6 clock cycles, but it will let you expand >> > the list of things indefinitely, going forward, instead of having >> > to keep a register dedicated for backward compatability, and then >> > somehow "grow a new one" when you need to do something similar to >> > this again, in the future. >> >> It will be an indirect if I have any say in it. :) Currently we use %fs in >> the >> kernel to address a segment that contains per-CPU data. I think that if we >> use >> a seg reg, then we should have it address a segment that contains per-KSE >> data. > > Didn't Terry want an additional level of indirection? If we > have %fs address a segment containing per-KSE data, then I'd > like to place pointers to both the KSE struct and the thread struct > (2 slots) in this segment (this would remove 1 level of indirection > to "current thread"). %fs is the indirection. :) -- John Baldwin -- http://www.FreeBSD.org/~jhb/ PGP Key: http://www.baldwin.cx/~john/pgpkey.asc "Power Users Use the Power to Serve!" - http://www.FreeBSD.org/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-arch" in the body of the message