Co-locate VM on a single/set of core(s)

us flag

I'm trying to understand certain impacts of virtualisation on performance by running benchmarks on VMs. I'm considering ESXi and Hyper-V as the hypervisors. I wanted to know if I can pin a VM to a particular core or set of cores. If possible, I could then pin 2 VMs to the same core and try reading into the effects when there's a memory intensive job running in both

djdomi avatar
za flag
Does this answer your question? [Can you help me with my capacity planning?](
cn flag
It does not - he asks for a specific manipulation of the scheduler (pinning 2 vm's to identical cores) so he can study the effects. THis is not the same as asking us to do his capacity planning.
ru flag

Pinning a VM to a specific set of cores limits the hypervisor's choices when scheduling vCPU cores to pCPUs cores. Pinning several VMs to the same set of cores very much resembles running them on a host with only that number of cores.

On the process level, this has nearly the same impact as running all processes on a single machine. How that interacts with memory-intensive access highly depends on the CPU type and the cache and memory subsystem, especially the cache sizes and the number of usable channels.


Post an answer

Most people don’t grasp that asking a lot of questions unlocks learning and improves interpersonal bonding. In Alison’s studies, for example, though people could accurately recall how many questions had been asked in their conversations, they didn’t intuit the link between questions and liking. Across four studies, in which participants were engaged in conversations themselves or read transcripts of others’ conversations, people tended not to realize that question asking would influence—or had influenced—the level of amity between the conversationalists.