| |
|
 |
|
 |
|
|
|
| |
|
|
xen-devel
Re: [Xen-devel] Offline state in scheduling
On 29/06/10 12:42, Yuyang Du wrote:
Is it right to say the time HVM waits for I/O equals the offline time (given no
administrator pauses)?
There are some I/O events that are handled inside of Xen (such as APIC
accesses); these don't cause a vcpu to be paused. I think in the normal
course of operation, an HVM vcpu is only paused when doing I/O. Other
reasons might be administrator pause, migration, save/restore, domain
creation, memory sharing / page swapping, and so on. But if you aren't
doing any of those, I think I/O done in QEMU would be the only reason.
I am testing apache web server in a HVM, and I find that vcpu blocking state
makes up a large portion. Since the HVM can not issue SCHED_block hypercalls,
so the blocking state means the VM is not cpu intensive and often executes HLT
to halt itself?
Yes. If you take a trace to include VMX / SVM events, and use xenalyze,
you should be able to see the HLT vmexit before blocking.
-George
_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel
|
|
|
| |
|
Home