On Tue, Jul 24, 2018 at 03:30:32PM -0600, Alan Somers wrote: > What are people's experiences with overcommitting CPUs in BHyve? I have an > 8-core machine that often runs VMs totalling up to 5 allocated CPUs without > problems. But today I got greedy. I assigned 8 cores to one VM for a big > build job. Obviously, some of those were shared with the host. I also > assigned it 8GB of RAM (out of 16 total). Build performance fell through > the floor, even though the host was idle. Eventually I killed the build > and restarted it with a more modest 2 make jobs (but the VM still had 8 > cores). Performance improved. But eventually the system seemed to be > mostly hung, while I had a build job running on the host as well as in the > VM. I killed both build jobs, which resolved the hung processes. Then I > restarted the host's build alone, and my system completely hung, with > top(1) indicating that many processes were in the pfault state. > > So my questions are: > 1) Is it a known problem to overcommit CPUs with BHyve? > 2) Could this be related to the pfault hang, even though the guest was idle > at the time?
VMWare's ESXi uses a special scheduler to do what it does. I wonder if it would be worthwhile to investigate implementing a scheduler in FreeBSD that provides decent performance for virtualized workloads. Thanks, -- Shawn Webb Cofounder and Security Engineer HardenedBSD Tor-ified Signal: +1 443-546-8752 Tor+XMPP+OTR: [email protected] GPG Key ID: 0x6A84658F52456EEE GPG Key Fingerprint: 2ABA B6BD EF6A F486 BE89 3D9E 6A84 658F 5245 6EEE
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