Keir Fraser wrote: > On 16/2/07 17:46, "Jeremy Fitzhardinge" <jeremy at goop.org> wrote: > > >> Keir Fraser wrote: >> >>> This initial patchset does not include save/restore support anyway, so in >>> fact it would be consistent to have CONFIG_PREEMPT configurable. I'm sure >>> that we are going to have some nasty bugs to fix up as a result, but we >>> can't fix them until we find them! Then we can convert our save/restore code >>> to use the freezer before submitting it for inclusion. >>> >> OK. So that makes the only config restriction the 100Hz ticks. >> > > We can extend the Xen timer interface quite easily and get rid of this one > too. In fact it doesn't *much* matter if the CONFIG_HZ differs from the Xen > ticker rate -- we modified the Linux timer ISR to handle timer interrupts at > arbitrary times already. The only drawback is that jiffies updates in burts > if CONFIG_HZ is higher than the actual tick rate, and this can affect some > calibration constants and cause Linux to print out some weird values at > start-of-day. > That's why we'd very much like to get a get_cpu_speed paravirt-op implemented. I think this would be useful to work around these problems for Xen as well. Zach
