Open Stack

Thanks for response,

Yes if i ping from remote machine to that VM i am getting timeout at
some interval.

My application is CPU intensive, it is not doing any disk operation,
actually this application is base on VoIP. so pure RTP traffic flowing
on network. small UDP packets.

On Thu, Dec 17, 2015 at 1:20 PM, Rick Jones <rick.jones2 at hpe.com> wrote:
> On 12/17/2015 08:11 AM, Satish Patel wrote:
>> Following is TOP command on guest machine, at this point i am getting
>> ping breaks
>
> Just to clarify, when you say "getting ping breaks" you mean that is when
> you start seeing pings not getting responses yes?
>
>> top - 16:10:30 up 20:46,  1 user,  load average: 4.63, 4.41, 3.60
>> Tasks: 165 total,   6 running, 159 sleeping,   0 stopped,   0 zombie
>> %Cpu0  : 15.1 us, 12.3 sy,  0.0 ni, 60.9 id,  0.0 wa,  0.0 hi,  0.3 si,
>> 11.4 st
>> %Cpu1  : 22.9 us, 17.2 sy,  0.0 ni, 51.4 id,  0.0 wa,  0.0 hi,  0.3 si,
>> 8.2 st
>> %Cpu2  : 28.8 us, 22.4 sy,  0.0 ni, 47.5 id,  0.0 wa,  0.0 hi,  1.0 si,
>> 0.3 st
>> %Cpu3  : 16.6 us, 15.0 sy,  0.0 ni, 66.4 id,  0.0 wa,  0.0 hi,  0.3 si,
>> 1.7 st
>> %Cpu4  :  9.8 us, 11.8 sy,  0.0 ni,  0.0 id, 75.4 wa,  0.0 hi,  0.3 si,
>> 2.6 st
>> %Cpu5  :  7.6 us,  6.1 sy,  0.0 ni, 81.4 id,  0.0 wa,  0.0 hi,  4.2 si,
>> 0.8 st
>> %Cpu6  :  8.1 us,  7.4 sy,  0.0 ni, 83.0 id,  0.0 wa,  0.0 hi,  1.4 si,
>> 0.0 st
>> %Cpu7  : 17.8 us, 17.8 sy,  0.0 ni, 64.1 id,  0.0 wa,  0.0 hi,  0.3 si,
>> 0.0 st
>> KiB Mem :  8175332 total,  4630124 free,   653284 used,  2891924
>> buff/cache
>> KiB Swap:        0 total,        0 free,        0 used.  7131540 avail Mem
>
> 75% wait time on a vCPU in the guest suggests the application(s) on that
> guest are trying to do a lot of I/O and bottlenecking on it.  I am not all
> that well versed on libvirt/KVM, but if there is just the one I/O thread for
> the VM, and it is saturated (perhaps waiting on disc) doing I/O for the
> VM/instance, that could cause other I/O processing like network I/O to be
> held-off, and it could be that either the transmit queue of the interface in
> the guest is filling as it goes to send the ICMP Echo Replies (ping
> replies), and/or the queue for the instance's tap device (the inbound
> traffic) is filling as the ICMP Echo Requests are arriving.
>
> I would suggest looking further into the apparent I/O bottleneck.
>
> Drifting a bit, perhaps...
>
> I'm not sure if it would happen automagically, but if the "vhost_net" module
> isn't loaded into the compute node's kernel you might consider loading that.
> From that point on, newly launched instances/VM on that node will start
> using it for networking and should get a boost.  I cannot say though whether
> that would bypass the VMs I/O thread. Existing instances should pick it up
> if you "nova reboot" them. (I don't think a reboot initiated from within the
> instance/VM would do it).
>
> Whether there is something similar for disc I/O I don't know - I've not had
> to go looking for that yet.
>
> happy benchmarking,
>
> rick jones
> http://www.netperf.org/
>
>