-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Zachary Amsden escreveu: > On Tue, 2007-10-30 at 00:02 +0100, Ingo Molnar wrote: >> * Zachary Amsden <[EMAIL PROTECTED]> wrote: > >>> Not every guest support paravirt, but for correctness, all guests >>> require TSC, which must be exposed all the way up to userspace, no >>> matter what the efficiency or accuracy may be. >> but if there's a perfect TSC available (there is such hardware) then the >> TSC _is_ the best clocksource. Paravirt now turns it off unconditionally >> in essence. > > No, if no paravirt clocksource is detected, nothing can override the > perfect TSC hardware clocksource rating of 400. And if a paravirt > clocksource is detected, it is always better than TSC.
Why always? tsc is the best possible alternative the _platform_ can provide. So the paravirt clocksource will be at best, as good as tsc. And if it is the case: why bother with communication mechanisms of all kinds, calculations, etc, if we can just read the tsc? Noting again: If the tsc does not arrive accurate to the guest, it will fail the tsc clocksource tests. So it will be rated zero anyway -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.7 (GNU/Linux) Comment: Using GnuPG with Remi - http://enigmail.mozdev.org iD8DBQFHJx1KjYI8LaFUWXMRAv0hAJ4sj0Z1FraYrgbU5Mj0pWOJGk6jtwCfc5xL jpTC273X0oqPTCR7NcVHJOI= =WPzV -----END PGP SIGNATURE----- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
