<div dir="ltr"><br><div class="gmail_extra"><br><div class="gmail_quote">On Tue, Mar 21, 2017 at 8:14 PM, FERNANDO FREDIANI <span dir="ltr"><<a href="mailto:fernando.frediani@upx.com" target="_blank">fernando.frediani@upx.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
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<p>Hello Yaniv.</p>
<p>Have a new information about this scenario: I have load-balanced
the requests between both vNICs, so each is receiving/sending half
of the traffic in average and the packet loss although it still
exists it lowered to 1% - 2% (which was expected as the CPU to
process this traffic is shared by more than one CPU at a time).<br>
However the Load on the VM is still high probably due to the
interrupts.</p>
<p>Find below in-line the answers to some of your points:<br>
</p><span class="">
<br>
<div class="m_-6724787778127745712moz-cite-prefix">On 21/03/2017 12:31, Yaniv Kaul wrote:<br>
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<div class="gmail_extra">So there are 2 NUMA nodes on the host?
And where are the NICs located?</div>
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Tried to search how to check it but couldn't find how. Could you
give me a hint ?</div></blockquote><div><br></div><div>I believe 'lspci -vmm' should provide you with node information per PCI device.</div><div>'numactl' can also provide interesting information. </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div bgcolor="#FFFFFF" text="#000000"><span class=""><br>
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<div> <br>
<span> </span></div>
BTW, since those are virtual interfaces, why do you need two
on the same VLAN?</div>
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Very good question. It's because of an specific situation where I
need to 2 MAC addresses in order to balance the traffic in LAG in a
switch which does only layer 2 hashing.<span class=""><br>
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<div> </div>
Are you using hyper-threading on the host? Otherwise, I'm
not sure threads per core would help.</div>
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Yes I have hyper-threading enabled on the Host. Is it worth to
enable it ?</div></blockquote><div><br></div><div>Depends on the workload. Some benefit from it, some don't. I wouldn't in your case (it benefits mainly the case of many VMs with small number of vCPUs).</div><div>Y.</div><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div bgcolor="#FFFFFF" text="#000000"><span class=""><br>
<br>
Thanks<br>
Fernando<br>
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<div bgcolor="#FFFFFF" text="#000000"><span class="m_-6724787778127745712m_-144604539708212250HOEnZb"></span>
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<div class="m_-6724787778127745712m_-144604539708212250h5"> <br>
<div class="m_-6724787778127745712m_-144604539708212250m_7680788519611111480moz-cite-prefix">On
18/03/2017 12:53, Yaniv Kaul wrote:<br>
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<div class="gmail_extra"><br>
<div class="gmail_quote">On Fri,
Mar 17, 2017 at 6:11 PM,
FERNANDO FREDIANI <span dir="ltr"><<a href="mailto:fernando.frediani@upx.com" target="_blank">fernando.frediani@upx.com</a>></span>
wrote:<br>
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<div>Hello
all.<br>
<br>
</div>
I have a
peculiar
problem here
which perhaps
others may
have had or
know about and
can advise.<br>
<br>
</div>
I have Virtual
Machine with 2
VirtIO NICs.
This VM serves
around 1Gbps of
traffic with
thousands of
clients
connecting to
it. When I do a
packet loss test
to the IP pinned
to NIC1 it
varies from 3%
to 10% of packet
loss. When I run
the same test on
NIC2 the packet
loss is
consistently 0%.<br>
<br>
</div>
From what I gather
I may have
something to do
with possible lack
of Multi Queu
VirtIO where NIC1
is managed by a
single CPU which
might be hitting
100% and causing
this packet loss.<br>
<br>
</div>
Looking at this
reference (<a href="https://fedoraproject.org/wiki/Features/MQ_virtio_net" target="_blank">https://fedoraproject.org/wik<wbr>i/Features/MQ_virtio_net</a>)
I see one way to
test it is start the
VM with 4 queues
(for example), but
checking on the
qemu-kvm process I
don't see option
present. Any way I
can force it from
the Engine ?<br>
</div>
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<div>I don't see a need for
multi-queue for 1Gbps.</div>
<div>Can you share the host
statistics, the network
configuration, the qemu-kvm
command line, etc.?</div>
<div>What is the difference
between NIC1 and NIC2, in the
way they are connected to the
outside world?</div>
<div> </div>
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<div>
<div>
<div>
<div><br>
</div>
This other reference (<a href="https://www.linux-kvm.org/page/Multiqueue#Enable_MQ_feature" target="_blank">https://www.linux-kvm.org/pag<wbr>e/Multiqueue#Enable_MQ_feature</a><wbr>)
points to the same
direction about
starting the VM with
queues=N<br>
<br>
</div>
<div>Also trying to
increase the TX ring
buffer within the
guest with ethtool -g
eth0 is not possible.<br>
</div>
<div><br>
</div>
Oh, by the way, the Load
on the VM is
significantly high
despite the CPU usage
isn't above 50% - 60% in
average.<br>
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<div><br>
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<div>Load = latest 'top'
results? Vs. CPU usage? Can
mean a lot of processes
waiting for CPU and doing very
little - typical for web
servers, for example. What is
occupying the CPU?</div>
<div>Y.</div>
<div> </div>
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Thanks<span class="m_-6724787778127745712m_-144604539708212250m_7680788519611111480HOEnZb"><font color="#888888"><br>
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<span class="m_-6724787778127745712m_-144604539708212250m_7680788519611111480HOEnZb"><font color="#888888">Fernando<br>
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<br>
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