Exam 2V0-21.19 topic 1 question 85 discussion

C is correct. http://virtualvillage.cloud/?p=456

Correct answer C Setting it to 1 results in 1 CPU thread per vNIC It is set to 2 as Default value which means 1 transmit CPU thread per VM Setting it to 3 results in 2 to 8 CPU threads per vNIC https://blogs.virtualmaestro.in/2020/06/20/how-to-optimize-virtual-machine-vnic-transmit-tx-vmkernel-thread-performance/

only C is correct - 8 threads

This is covered in Opt and Scale Course (but for reference I will use virtualmaestro blog) : https://blogs.virtualmaestro.in/2020/06/20/how-to-optimize-virtual-machine-vnic-transmit-tx-vmkernel-thread-performance/ How to configure CPU threads for vNIC? This feature can be enabled on per VM level by editing VMX (EthernetX.ctxPerDev=“#”) or on host level (Net.NetVMTxType = ‘#’). Here, # represents the value to be used as described below. Acceptable values for Net.NetVMTxType and EthernetX.ctxPerDev are 1, 2, or 3 where, Setting it to 1 results in 1 CPU thread per vNIC It is set to 2 as Default value which means 1 transmit CPU thread per VM Setting it to 3 results in 2 to 8 CPU threads per vNIC

For VMs that require a higher transmit rate and multiple simultaneous TCP streams, multiple CPU threads can be used per vNIC. Up to eight threads can be used by the vNIC, depending on the number of streams. https://blogs.virtualmaestro.in/2020/06/20/how-to-optimize-virtual-machine-vnic-transmit-tx-vmkernel-thread-performance/#:~:text=Up%20to%20eight%20threads%20can,on%20the%20number%20of%20streams.

answer is 8 threads per vNIC. VM max vNIC to assign is 10 but that is different

D https://configmax.vmware.com/guest?vmwareproduct=vSphere&release=vSphere%206.7&categories=1-0

Correct answer is C

Correct Answer is D https://configmax.vmware.com/guest?vmwareproduct=vSphere&release=vSphere%206.7&categories=1-0

https://configmax.vmware.com/guest?vmwareproduct=NSX%20Data%20Center%20for%20vSphere&release=NSX%20for%20vSphere%206.4.6&categories=17-0

Correct answer C. Checked in egzam.

This is a hard one, could not find a good answer for it, bu it agree on 8 being the maximum. https://www.vmware.com/content/dam/digitalmarketing/vmware/en/pdf/techpaper/performance/Perf_Best_Practices_vSphere65.pdf (Page 55) When multiple receive queues are enabled, the feature by default configures 1, 2, 4, or 8 receive queues in a virtual machine, choosing the largest of these values less than or equal to the number of vCPUs in that virtual machine https://kb.vmware.com/s/article/2061598 - Select the minimum value from the number of vCPUs, configured maximum number of Rx queues and the number 8. - Round off the selected minimum to the nearest power-of-2 number in descending direction

Right answer is 8, alot of people get confused here is a link for "Virtual Machine Tx threads explained" https://nielshagoort.com/2017/07/18/virtual-machine-tx-threads-explained/

trust me it is 16 RX Queues and 8 TX Queues ,this is the maximum queues you an have at this point . The question here is not specific , 10 is not a 2^n number . 8 is the appropriate answer . Note :10 is the maximum number of vNICS that can be configured on a VM, the question is about queues. They didnt mention if its a tx queue or an rx queue.

8 Threads/vNIC

Multiple Threads per vNIC For VMs that require a high transmit rate and multiple simultaneous TCP streams, you can enable multiple CPU threads per vNIC. Up to eight separate threads can be created per vNIC.

here are the improvements being made ? VMXNET 3 optimization Using copy TX for small messages size (<=256B) Optimized usage of pinned memory Physical NIC improvements Native driver support for Intel cards (removes overhead of translating from VMkernel to VMKLinux data structures) CPU Scheduling Improvements Up to 8 separate threads can be created per vNIC To enable on VM level add: ethernetX.ctxPerDev = “3” to vmx file