[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Xen-devel] [Patch] time resolution fix.

On 19 Mar 2006, at 14:28, Keir Fraser wrote:

        I have a much detail description in the attached slide, hope
this helpful.

Well, freezing the TSC while a guest is descheduled is not very nice at all, but I can imagine it stops you getting time went backwards messages if you are also forcibly re-setting the TSC on PIT ticks. :-)

The freezing is I guess why you have the new hook schedule_out(), which I'm also not madly keen on. Especially since this must surely be a short-term workaround (you don't intend to TSC freeze as long-term solution, right?).

Actually, I now recall we were going to use this approach long term to ensure the guest calibrates TSC rate correctly during boot. But then we are going to turn it off the first time the guest reads wall-clock time (via RTC, for example). But that means we will need the schedule_out() hook long term, and that makes your patch less unattractive. I'll take another look and reconsider it.

 -- Keir

Xen-devel mailing list



Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.