Date: Thu, 13 Nov 1997 19:07:58 +0000 (GMT) From: Terry Lambert <tlambert@primenet.com> To: rminnich@Sarnoff.COM (Ron G. Minnich) Cc: freebsd-hackers@FreeBSD.ORG Subject: Re: BSDI F0 bug workaround implementation Message-ID: <199711131907.MAA28899@usr08.primenet.com> In-Reply-To: <Pine.SUN.3.91.971113092136.5504A-100000@terra> from "Ron G. Minnich" at Nov 13, 97 09:31:07 am
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> I'm not sure I understand the full implications of the impact of this > hack, although it is worrisome. Judging by what my pentium book says about > the layout of the IDT, it seems like it will increase interrupt latency > for page faults and many maskable interrupts. Can anyone more > knowledgeable than I comment on this? Page fault overhead on freebsd is > pretty high: would a short-cut make sense that does not go through the > full vm system for this? Otherwise page fault overhead may come close to > doubling ... Only the first 7 IDT entries are affected (at least in the Linux workaround), not the whole table. On the minus side, the impact *is* non-zero. Like the FPU bug, since a workaround exists, it's likely to be swept under the software as well. 8-(. Terry Lambert terry@lambert.org --- Any opinions in this posting are my own and not those of my present or previous employers.
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