RE: [Xen-users] CPU activity: top and xm top

["Petersson, Mats" <Mats.Petersson@xxxxxxx>]

> -----Original Message-----
> From: Igor Chubin [mailto:igor@xxxxxxx] 
> Sent: 11 April 2007 10:50
> To: Petersson, Mats
> Cc: Igor Chubin; Xen-users@xxxxxxxxxxxxxxxxxxx
> Subject: Re: [Xen-users] CPU activity: top and xm top
> 
> ...
> > > I wanted to inspect interrupts activity using sar, 
> > > but without success. Unfortunately sar doesn't report interrupts
> > > activity under Xen :(
> > > (May be I can use /proc/interrupts and get information from this
> > > file? Will it be correct?)
> > 
> > It should be correct as to what Dom0 is doing, it won't 
> show interrupts
> > that go to Xen but are "hidden" from Dom0 (but I doubt that 
> is many). 
> 
> Will interrupts processed by hypervisor itself 
> (without help of the Linux kernel) 
> be visible in this file?

No, that's exactly what I said: Xen will process a few of the interrupts
without handing them to Dom0. 

I have a hard time thinking those should amount to 20% tho'. 

However, bear in mind that when you start xend, it sets your network
card to promiscuous mode, which means that it's going to accept ALL
incoming traffic present on the network segment you're on, even if it's
not addressed to your machine. If you're on the same network as a few
busy computers, you'll receive quite a bit of network traffice that
isn't for you (but still received by your machine, because it's on the
same network). You should see that in /proc/interrupts for your network
card tho'. 

--
Mats
> 
> 
> > > 
> > > So my machine is idle but I have 20% of CPU activity for domain 0.
> > > The question is: How can I get exactly know for what is this 
> > > 20% spending?
> > > What tools (or interfaces e.g. /proc files) can I use for this?
> > 
> > Xenoprofile is probably your best bet. 
> > 
> 
> Thank you for the idea.
> 
> -- 
> WBR, i.m.chubin
> 
> 
> 
> 



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