Here's an extract from my kern.log just for one hour:
Dec 6 22:01:32 host kernel: [94357.691710] spurious APIC interrupt on CPU#6, should never happen.
Dec 6 22:01:41 host kernel: [94366.568217] spurious APIC interrupt on CPU#0, should never happen.
Dec 6 22:05:30 host kernel: [94594.952440] spurious APIC interrupt on CPU#4, should never happen.
Dec 6 22:07:17 host kernel: [94702.508002] spurious APIC interrupt on CPU#3, should never happen.
Dec 6 22:12:54 host kernel: [95038.524471] spurious APIC interrupt on CPU#0, should never happen.
Dec 6 22:16:59 host kernel: [95283.704960] spurious APIC interrupt on CPU#1, should never happen.
Dec 6 22:17:46 host kernel: [95330.274178] spurious APIC interrupt on CPU#0, should never happen.
Dec 6 22:17:46 host kernel: [95330.954803] spurious APIC interrupt on CPU#7, should never happen.
Dec 6 22:19:01 host kernel: [95405.219228] spurious APIC interrupt on CPU#0, should never happen.
Dec 6 22:20:31 host kernel: [95495.337533] spurious APIC interrupt on CPU#4, should never happen.
Dec 6 22:20:59 host kernel: [95523.587393] spurious APIC interrupt on CPU#4, should never happen.
Dec 6 22:21:00 host kernel: [95523.805565] spurious APIC interrupt on CPU#4, should never happen.
Dec 6 22:21:31 host kernel: [95555.436663] spurious APIC interrupt on CPU#4, should never happen.
Dec 6 22:22:48 host kernel: [95631.711465] spurious APIC interrupt on CPU#6, should never happen.
Dec 6 22:23:44 host kernel: [95687.975849] spurious APIC interrupt on CPU#0, should never happen.
Dec 6 22:27:09 host kernel: [95892.952456] spurious APIC interrupt on CPU#0, should never happen.
16 messages per hour -- it is not innocuous, and I have just a few VMs running.
IMHO, there's an error in Workstation 11 utilizing inter-processor interrupts between virtual CPUs.
Anyway, I've disabled the optimization, and no more messages for me.
Thank you very much for your reply!