CPU Ready Revisted – Quick Reference Charts

I've written in the past about how high CPU Ready values can cause performance problems in VMware vSphere environments.  For those who don't know, CPU Ready is a measure of the amount of time that a guest VM is ready to run, but the VMware ESXi CPU Scheduler on the host is not able to immediately allocate cycles to the guest because it is busy doing work for other VM's.  CPU Ready values are exposed through ESXTOP and in the vSphere Client. I'm often called into customer environments to do performance troubleshooting, and CPU Ready is one of the first performance measurements I check my … [Read more...]

High CPU Ready, Poor Performance

**Update** January 2013: You've probably found your way here by doing a search for 'High CPU Ready in VMware' or something to that effect.  Welcome, I'm glad you're here.  Give this article a read as it still has relevant content, then check out this newer post on CPU Ready, with some handy quick reference charts and more detailed info on the condition: http://vmtoday.com/2013/01/cpu-ready-revisted-quick-reference-charts/.  Thanks for reading! --Josh I ran into an issue with a customer today where a VM was performing terribly.  From within the guest OS (a Windows 2003 application server … [Read more...]