RE: [Xen-ia64-devel] [IPF-ia64] with Cset 10690, creating a VTImake xen0 hang

["Zhang, Xiantao" <xiantao.zhang@xxxxxxxxx>]

Hi Alex,
        Our QA team reported that xen0 would hang after creating VTi domain 
@CSet 10688-10694. Should we reverse the logic of vcpu_itr_d first ?  Maybe we 
can find out the real bottleneck later.:)
Thanks & Best Regards
-Xiantao

OTC,Intel Corporation

> -----Original Message-----
> From: Atsushi SAKAI [mailto:sakaia@xxxxxxxxxxxxxx]
> Sent: 2006年7月11日 21:46
> To: Alex Williamson; Zhang, Xiantao
> Cc: Isaku Yamahata; xen-ia64-devel@xxxxxxxxxxxxxxxxxxx
> Subject: Re: [Xen-ia64-devel] [IPF-ia64] with Cset 10690, creating a VTImake
> xen0 hang
> 
> Hi, Alex
> 
> Sorry for late.
> 
> I found your problem(boot time difference w/ PAL_HALT_LIGHT emulation patch)
> occurred in SMP(credit).
> But, it does not occurred in UP, SMP(bvt) and SMP(credit w/ affinity).
> 
> I think the emulation of pal_halt_light for domU
> does not good work for DomVTI boot up
> under credit scheduling w/o affinity.
> 
> And consider the Xiantao survey,
> qemu make heavy I/O operations at the boot up.
> 
> Consider the above two conditions,
> I think credit scheduler algorithm does not consider
> the block state.(caused by pal_halt_light emulation)
> So I want to switch off the vcpu migration at heavy load
> 
> 
> I planned as follows.
> 
> 1)In the short term,
> I want to avoid this problem by
> HALT the PAL_HALT_LIGHT emulation while DomVTI boot up.
> or
> Lock VCPUs migrations while DomVTI boot up.
> (when Credit scheduler runs)
> 
> 2)In the long term,
> I will make a patch to avoid this problem.
> (Consider the heavy io w/ vcpu migration)
> 
> N.B.
> I checked under CS:10559.(original patch made)
> 
> Thanks,
> Atsushi SAKAI
> 
> 
> 
> 
> 
> >On Tue, 2006-07-11 at 19:42 +0800, Zhang, Xiantao wrote:
> >> Hi Alex,
> >>    Seems this issue was caused by Cset 10688. In vcpu_itr_d, the current
> >> logic purges vhpt with cpu_flush_vhpt_range but it is very heavy to
> >> xen0. When creating VTi domain @ early stage, IO operation is very
> >> excessive, so qemu was scheduled out and in very frequently and this
> >> logic was executed every time. In addition, cpu_flush_vhpt_range using
> >> identity map to purge vhpt may cause more tlb miss due to no TR map.
> >> If remove vcpu_flush_tlb_vhpt_range logic although it definitely
> >> needed, seems VTi becomes healthy. Maybe potential bugs exist there.:)
> >
> >   Thanks for investigating Xiantao.  Isaku, any thoughts on how to
> >regain VTI performance?  Thanks,
> >
> >     Alex
> >
> >--
> >Alex Williamson                             HP Open Source & Linux Org.
> >
> >
> >_______________________________________________
> >Xen-ia64-devel mailing list
> >Xen-ia64-devel@xxxxxxxxxxxxxxxxxxx
> >http://lists.xensource.com/xen-ia64-devel
> >
> 
> 
> 

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