RE: [Xen-ia64-devel] [IPF-ia64] with Cset 10690, creating aVTImakexen0 hang

["Xu, Anthony" <anthony.xu@xxxxxxxxx>]

>From: Atsushi SAKAI 
>Sent: 2006?7?12? 19:05
>My primary motivation is correct display of xenmon.py and xentop in BVT/CREDIT.
>(N.B. SEDF displayed as same as x86, but BVT/CREDIT are not)
>If only domU emulation is applied, it is a half way from my motivation.
>Is dom0 dispatch another home work?
>

I suspect the slowness is not due to dom0 being scheduled out, but due to 
hlt_timer
didn't work as expected.
           set_timer(&v->arch.hlt_timer, vcpu_get_next_timer_ns(v)); 
           do_sched_op_compat(SCHEDOP_block, 0);
There is a time window between set_timer and dom0 being scheduled out, and 
psr.i 
is 1. So if hlt_timer fires before do_sched_op_compat being called, dom0 will 
not be woken up by hlt_timer, and there is no timer interrupt for dom0 until 
domo 
is woken up ,yes, dom0 can be woken up by other external interrupts, but not by
timer interrupt. And since dom0 is involved in VTIdomain bootup, this may lead 
to slowness of VTIdomain bootup.

Above is my analysis, there isn't any evidence.

You can do experiment to check it.
Change above code sequence as following, this may reduce the impact of time 
window.

set_timer(&v->arch.hlt_timer, cycle_to_ns(local_cpu_data->itm_delta)+NOW());
do_sched_op_compat(SCHEDOP_block, 0);

_______________________________________________
Xen-ia64-devel mailing list
Xen-ia64-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-ia64-devel