Tuesday, September 30, 2008

You cannot do SMP in VMWare Player

VMWare player doesn't support SMP, though you might see a processor which is capable of SMP. Here is a quote from the VMWarePlayer manual:
Virtual SMP
VMware Player does not support Virtual SMP™. You cannot use VMware
virtual machine that has more than one virtual processor assigned.

For e.g. when I look at /proc/cpuinfo, I am seeing only one processor though my VMWare Player emulates "Intel(R) Core(TM)2 Duo CPU T7300 @ 2.00GHz". When I inspect the boot messages, I realized that my Linux switch to uniprocessor configuration while booting:
[ 7.135461] SMP alternatives: switching to UP code
[ 7.135523] Freeing SMP alternatives: 11k freed

So if you are trying to test any multithreaded appplication, beware that the results you will get in your VMWare Player's Linux and the real Linux will not be the same. Your VMWare Player's version is likely to give you worse results as its running in uniprocessor mode.

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