libvirt users - May 2013 - Re: Fwd: Does Set Block IO tune take effect in the same session.

On 27.05.2013 12:36, vikrant verma wrote:
> Hello Michal,
> 
> I am using the following code - 
> 
>  virDomainSetInterfaceParameters(dom, "vnet0",
networkParainfoPtr,
> nparams,0);
> 
> before calling this i am assigning the following Inbound values
> 
> inbound.average = 10 (10 kbps)
> inbound .peak = 10
> inbound.burst = 10
I suspect this way too low burst value. Try leaving the limit and it
should work correctly.

Michal

Hello Michal,

Throttling is working now after setting inbound.average = 10  (i have set
other values to 0 )
But i am observing an inconsistent behavior in the observed throttling
bandwidth

when i set  inbound.average = 10 , i observed bandwidth of 24 kbps
when i set  inbound.average = 100 , i observed bandwidth of 186 kbps
when i set  inbound.average = 1024 , i observed bandwidth of 2MBps

i measured the above by doing scp of a 4MB file from host to VM. Is this
behavior is expected?

Regards,
Vikrant



On Tue, May 28, 2013 at 6:57 PM, Michal Privoznik
<mprivozn@redhat.com>wrote:
> On 27.05.2013 12:36, vikrant verma wrote:
> > Hello Michal,
> >
> > I am using the following code -
> >
> >  virDomainSetInterfaceParameters(dom, "vnet0",
networkParainfoPtr,
> > nparams,0);
> >
> > before calling this i am assigning the following Inbound values
> >
> > inbound.average = 10 (10 kbps)
> > inbound .peak = 10
> > inbound.burst = 10
>
> I suspect this way too low burst value. Try leaving the limit and it
> should work correctly.
>
> Michal
>

On 31.05.2013 07:05, vikrant verma wrote:
> Hello Michal,
> 
> Throttling is working now after setting inbound.average = 10  (i have
> set other values to 0 )
> But i am observing an inconsistent behavior in the observed throttling
> bandwidth
> 
> when i set  inbound.average = 10 , i observed bandwidth of 24 kbps
> when i set  inbound.average = 100 , i observed bandwidth of 186 kbps
> when i set  inbound.average = 1024 , i observed bandwidth of 2MBps
> 
> i measured the above by doing scp of a 4MB file from host to VM. Is this
> behavior is expected?
> 
I don't think so. So your other values are set to 0? Can you share the
actual <bandwidth/> element from 'virsh dumxpl $dom'?

However, I might be hitting the same issue:

# tc -s class show dev vnet0
class htb 1:1 root leaf 2: prio 0 rate 80000bit ceil 80000bit burst 1600b cburst
1600b
 Sent 5146972 bytes 3540 pkt (dropped 0, overlimits 0 requeues 0) 
 rate 536752bit 45pps backlog 0b 4p requeues 0 
 lended: 359 borrowed: 0 giants: 0
 tokens: -937499999 ctokens: -937499999

class sfq 2:36c parent 2: 
 (dropped 0, overlimits 0 requeues 0) 
 backlog 103018b 4p requeues 0 
 allot 1520 

We can see both rate and ceil being 80kbit however the current rate being
536kbit. I wonder what's going on and how to fix this.
> Regards,
> Vikrant
Michal