Context Switching ?

[multirotor]

After troubleshooting the performance of several database servers running under ESX3.01, I found some threads about Context Switching.

The VM's are Windows 2003 2VCPU IBM DB2 machines with context switching consistently over 5000cswitches/sec with peaks going up to 30000cswitches/sec.

The host is a DL585G2 with 4 dual cores.

I have attached a Sysinternals Process Explorer screen copy.

It is the db2syscs.exe process generating the context switches and it is running 43 threads on its own.

Is there anything that can be done to improve the handling of context switches apart from trying to reduce them ?!

Any magic vmx file setting ?

[TCronin]

Try going to 1 vcpu, it will be easier for the scheduler to give access to 1 pcpu at a time. 2 vcpus need to be always scheduled at the same time, which is usually troublesome.

[multirotor]

1VCPU is what we are coming from. Performance actually improved with the second CPU but probably the overhead also increased. I know one VCPU is easier on the host but I am looking for the best possible performance under ESX, even if that means sacrifices for other VMs.

[TomHowarth]

Setting Processor affinity will help, however this will sacrifice the ability to VMotion the guest.

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Kind Regards

Tom,

[meistermn]

Did you have a solution?