Re: [Xen-ia64-devel] [PATCH] NEW_TLBFLUSH_CLOCK_PERIOD_SOFTIRQ is notregistered.

[Isaku Yamahata <yamahata@xxxxxxxxxxxxx>]

Hi Anthony.

On Mon, Jan 29, 2007 at 02:31:14PM +0800, Xu, Anthony wrote:

> Could you elaberate the purpose of new_tlbflush_clock_period?

Tlb flush clock is the optimization to try to remove unnecessary flush of
mCPU tlb cache or vhpt by NEED_FLUSH().
It uses a single counter, tlbflush_time, which is incremented when
mCPU tlb cache or vhpt is flushed.
When the counter overflows, something must be done.
new_tlbflush_clock_period() does it.


> BTW, Intel experienced domain panic or domain disppear after the very long 
> run(after 24 hours).
> We are investigating this.

only VT-i domain or only domU or both?

You can disable tlb flush clock by setting xen_ia64_tlbflush_clock=n
in xen's configuration file so that you can determine whether the root
cause is tlbflush clock or not.
I didn't recently compiled with xen_ia64_tlbflush_clock=n though.

Or you can shorten the time to call new_tlbflush_clock_period() by
defining WRAP_MASK as 0x000003FFU (or smaller value) in
xen/arch/ia64/xen/flushtlb.c.
Thus you can distinguish the root cause from tlbflush clock.


> Kouya SHIMURA write on 2007年1月26日 19:06:
> > Hi
> > 
> > NEW_TLBFLUSH_CLOCK_PERIOD_SOFTIRQ is used but not registered.
> > I've never experienced but system will panic in the very long run.
> > I wonder why Isaku missed it.

Ouch!
It doesn't cause panic, but it just becomes slow.
So I missed it.

-- 
yamahata

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