<html><head><meta http-equiv="Content-Type" content="text/html charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div class="">Hi, </div><div class=""><blockquote type="cite" class=""><div class=""><p class=""> When a vm is mapped to a flavor using dpdk, do all the vcpus the VM uses have to 'pinned' to use dpdk, thus this value means the total number of vcpus available to VMs needing dpdk?</p></div></blockquote></div><div class=""><div class="">I don’t think that Nova CPU pinning should be mandated once you choose to use DPDK on that Compute Host.</div><div class="">However, page</div><div class=""><a href="https://specs.openstack.org/openstack/fuel-specs/specs/9.0/support-numa-cpu-pinning.html" class="">https://specs.openstack.org/openstack/fuel-specs/specs/9.0/support-numa-cpu-pinning.html</a></div><div class="">really indicate it is mandated.</div><div class=""><br class=""></div><div class="">But I think that the idea could be that you are enforced to specify total number number explicitly, because the guideline configuration </div><div class="">is to enforce some CPUs for host OS ‘separately’?</div><div class=""><blockquote type="cite" class=""><div class=""><p class="">When a vm is mapped to a flavor using dpdk, do all the vcpus the VM uses have to 'pinned' to use dpdk, thus this value means the total number of vcpus available to VMs needing dpdk?</p></div></blockquote></div><div class="">I would say that it is ‘all host CPUs that should be available to _all_ VMs’. First of all, I think that configuration where you have both DPDK and non-DPDK physical adapters is uncommon</div><div class="">(hmmmm, vNIC plugging could be trickier…). Second of all, this perspective of Nova doesn’t have such direct relation with DPDK acceleration.</div><div class=""><div class="">So to CPUs running on 'all minus n’ host CPUs where n is number of CPUs you have for DPDK and probably you must decide on having something for host OS.</div></div><div class="">Otherwise all CPUs will end up in isolcpus and most likely host Linux won’t boot/will misbehave.</div><div class=""><br class=""></div><div class=""><div class="">But forcing you to indicate Nova CPUs doesn’t mean that you shouldn't enforced to use actual 1 guest CPU -1 host CPU pinning.</div><div class="">In case you won’t touch flavor keys defining then I expect that Nova just will put range like </div><div class=""><vcpu placement='static' cpuset='3-5,9-11'>1</vcpu> for all your VMs in Libvirt.</div><div class="">And then from your perspective the behaviour won’t change significantly. </div></div><div class=""><br class=""></div><div class=""><br class=""></div><div class="">BR, </div><div class="">Konstantin</div></div><div class=""><br class=""></div><div class=""><br class=""></div><div class=""><br class=""></div><br class=""><div><blockquote type="cite" class=""><div class="">On Feb 12, 2017, at 12:39 AM, - - <<a href="mailto:super@sxyninja.com" class="">super@sxyninja.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class="">
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<div class=""><p class="">Hello,</p><p class="">I am adding some new hosts to my MOS 9.2 fuel deployment, and I want to implement dpdk on the 2 new hosts. I have fuel setup with the experimental options so I can see the settings when adding the new hosts.</p><p class="">My question is relating to the node attributes section. In the documents for showing how to setup dpdk, it states to setup nova cpu pinning along with the dpdk cpu pinning.</p><p class="">I get that the dpdk cpu pinning is the number of cpus allocated for processing of the packets based on nic speed.</p><p class="">I don't see any information on exactly what the value of nova cpu pinning should be when doing only dpdk (no sriov). When a vm is mapped to a flavor using dpdk, do all the vcpus the VM uses have to 'pinned' to use dpdk, thus this value means the total number of vcpus available to VMs needing dpdk?</p><p class="">I just want to make sure I understand these values when setting this up, so I do it correctly.</p><p class="">Thanks,</p><p class="">DG</p></div>
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