Date: Wed, 22 Nov 2000 16:04:02 -0800 (PST) From: John Baldwin <jhb@FreeBSD.org> To: Daniel Eischen <eischen@vigrid.com> Cc: bright@wintelcom.net, jlemon@flugsvamp.com, arch@FreeBSD.org, Terry Lambert <tlambert@primenet.com> Subject: Re: Thread-specific data and KSEs Message-ID: <XFMail.001122160402.jhb@FreeBSD.org> In-Reply-To: <Pine.SUN.3.91.1001122182015.7920C-100000@pcnet1.pcnet.com>
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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 <jhb@FreeBSD.org> -- 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
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