Date: Fri, 22 Nov 2002 14:59:50 -0800 From: Terry Lambert <tlambert2@mindspring.com> To: John Baldwin <jhb@FreeBSD.org> Cc: current@FreeBSD.org, Scott Sipe <cscotts@mindspring.com>, Vallo Kallaste <kalts@estpak.ee> Subject: Re: DP2 Fatal Trap Message-ID: <3DDEB6E6.7E61E241@mindspring.com> References: <XFMail.20021122105742.jhb@FreeBSD.org>
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John Baldwin wrote: > >> > Is it any help to know that my problems on P4 stopped after enabling > >> > DISABLE_PSE? Initially I had both of these enabled, but seems that > >> > one is enough. Just FYI. > >> > >> If we can verify that DISABLE_PG_G has no effect then that would be > >> nice. > > > > It has an effect: writing CR3 or a TSS resulting in a changed CR3 > > will not invalidate TLB entries with the G flag set, if PGE is set > > in CR4. > > I know what PG_G does, Terry. My question is that if DISABLE_PG_G has > no effect on the _problems_ people are having. It can have an effect, if the problem is being exhibited on a P3 or an AMD processor, but not on a P4, unless it has 512M of memory; the jury is out on other memory sizes, after Matt Dillon's dynamic sizing changes (my own suggestion in this area was to conservatively not go overboard in allocating a multiplier of physical memory for page mappings, when doing so would push the space the mappings could cover well over the available physical address space, if you'll remember). I think the processor in the bug report that started this thread was an AMD K6? There really is a CPU bug, John, and the new FreeBSD locore.s code is triggering it. A stock FreeBSD 4.4, for example, will not exhibit this problem, on the same hardware. -- Terry To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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