<div dir="ltr"><br><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><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div><div><div><div><div><div><div><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/<wbr>wiki/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></div></div></div></div></blockquote><div><br></div><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><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><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/<wbr>page/Multiqueue#Enable_MQ_<wbr>feature</a>) 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></div></div></div></blockquote><div><br></div><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><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div><div><br></div>Thanks<span class="HOEnZb"><font color="#888888"><br></font></span></div><span class="HOEnZb"><font color="#888888">Fernando<br><div><div><div><div><br><br></div></div></div></div></font></span></div>
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