Date: Sun, 22 Dec 1996 22:53:02 +0100 From: Poul-Henning Kamp <phk@critter.tfs.com> To: "John S. Dyson" <toor@dyson.iquest.net> Cc: smp@freebsd.org Subject: Re: P6 problem idea Message-ID: <26009.851291582@critter.tfs.com> In-Reply-To: Your message of "Sun, 22 Dec 1996 12:24:35 EST." <199612221724.MAA07051@dyson.iquest.net>
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In message <199612221724.MAA07051@dyson.iquest.net>, "John S. Dyson" writes: >> >> >> John Dyson has enabled the "Global" bit on some parts of the kernel. >> This makes the marked pages immune to TLB flushes. Could this be the >> reason for the P6 Problems ? >> >> I belive there is a bit in a control register that will enable/disable >> this, it's probably in locore.s somewhere. >> >If you want to test that -- all you have to do is to disable the >setting of PG_G in locore and in pmap. You can also optionally >turn off the capability (but you still need to disable all of the >PG_G bit setting) by not setting the CR4_PGE bit in cr4 also. > >This *could* be the problem, because you need to do the single page >updates when the PG_G bit has been set (or there are more complex ways >of doing it also.) The global update will just not work... (Of course, >that is much of the purpose of the PG_G bit :-)). Well, we might have to be more selective about what we "Globalize" then... -- Poul-Henning Kamp | phk@FreeBSD.ORG FreeBSD Core-team. http://www.freebsd.org/~phk | phk@login.dknet.dk Private mailbox. whois: [PHK] | phk@tfs.com TRW Financial Systems, Inc. Power and ignorance is a disgusting cocktail.
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