Date: Sun, 20 Feb 2000 13:48:49 +1100 From: Patryk Zadarnowski <patrykz@ilion.eu.org> To: Arun Sharma <adsharma@sharmas.dhs.org> Cc: freebsd-hackers@FreeBSD.ORG Subject: Re: 64bit OS? Message-ID: <200002200248.NAA03808@mycenae.ilion.eu.org> In-Reply-To: Your message of "Sat, 19 Feb 2000 18:39:19 -0800." <20000219183919.C23349@sharmas.dhs.org>
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> On Sun, Feb 20, 2000 at 12:42:14PM +1100, Patryk Zadarnowski wrote: > > One more thing about GPTs (I thought I'll leave that till last. ;) > > Jochen Liedtke holds a German patent on them, although he will > > probably be fairly easily convinced to give FreeBSD rights to use > > them. I'll be happy to ask (if we're interested.) > > It looks like the hardware has to implement GPTs and know how to > walk them. How can FreeBSD use them without hardware support ? No it doesn't. We've got software GPT implementations for both MIPS64 and Alpha, and they're both peform very well in our somewhat hostile SASOS conditions. I'm not sure why you think that a hardware walk is necessary: the only reason why IA-64 walks VPHT in hardware *at all* is to minimize the impact on the pipeline and improve ILP: remember that the IA-64 hardware walk is *advisory* -- that is, the OS still must supply software TLB refill handlers, even if it uses a linear page table. Specifically, even though the simulator may not display that behaviour, Itanium aborts the VPHT walk early in quite a few cornel cases, even if completing the walk would avoid a TLB miss. Pat. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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