Date: Thu, 23 Oct 2008 13:57:56 +0200 From: =?utf-8?Q?Dag-Erling_Sm=C3=B8rgrav?= <des@des.no> To: "Attilio Rao" <attilio@freebsd.org> Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org, Jung-uk Kim <jkim@freebsd.org> Subject: Re: svn commit: r184108 - head/sys/i386/i386 Message-ID: <86bpxb34mz.fsf@ds4.des.no> In-Reply-To: <3bbf2fe10810220853r34256b59y1fe57f49eca2014@mail.gmail.com> (Attilio Rao's message of "Wed, 22 Oct 2008 17:53:50 %2B0200") References: <200810210431.m9L4V7Pb088978@svn.freebsd.org> <3bbf2fe10810210307t664cc8a2s62606f03427286f3@mail.gmail.com> <200810211605.46927.jkim@FreeBSD.org> <3bbf2fe10810220853r34256b59y1fe57f49eca2014@mail.gmail.com>
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"Attilio Rao" <attilio@freebsd.org> writes: > I think it is silly we have different quirks flag states for TSC. We > should just having a table assuming that the TSC is safe to use in SMP > environments and gets rid of any other flag (in this case, for amd64 > based machine, the logic could, for example, check if the CPU is P > state invariant and assume it is safe, etc.) No, these are two entirely different things. An SMP-safe TSC is a TSC that is synchronized across cores / packages. A P-state invariant TSC is a TSC that does not vary with the CPU frequency. One does not imply the other, and in many cases (if not most), there is no way to detect programmatically that the TSC is SMP-safe or P-state invariant or both. DES --=20 Dag-Erling Sm=C3=B8rgrav - des@des.no
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