VMware Cloud Community
big_vern
Enthusiast
Enthusiast

CPU ready time - how to interpert

Hi,

We have 84 VMs, with a total of 97 vCPUs assigned.

These run on x 5 HP balde, with 40 CPU cores in total (each balde has x4 dual core CPUs)

We are seeing high %ready times for a significant number of VMs (using ESXTOP some are running at over %20 almost constantly and spike to 70%). When I logon to the console of the VM the VM is responsive. The apps however are rreported to be running slowly.

Are these figures stupidly high?

I have been relying on the 'CPU usage' bar graph on the 'summary' tab for the ESX server and this only shows about 25% usage, so why the high ready time?? can someone explain it please.

For the problem VMs again the CPU usage is only about 50% but they still have high ready times.

cheers guys, and gals.

Reply
0 Kudos
2 Replies
RParker
Immortal
Immortal

Ready times have nothing to do with usage, it has to do with contention. Your CPU is waiting for a cycle to service the usage in a VM.

Ready means the CPU is 'ready' and its waiting to be used.

So this usually indicates one of two things, multi CPU in a VM which is not utilized properly, or too many VMs on a host. So of these VM's how many are multi CPU and how many VM's are running on the host. The only way to resolve it is to remove the CPU and ONLY make the VM's single CPU (change the hal in those Windows VM's to uniprocessor) which requires a reboot until the problem goes away.

Reply
0 Kudos
AWo
Immortal
Immortal

You may find this link helpful: http://communities.vmware.com/docs/DOC-9279


AWo

VCP / vEXPERT 2009

vExpert 2009/10/11 [:o]===[o:] [: ]o=o[ :] = Save forests! rent firewood! =
Reply
0 Kudos