Overcommitting cpus system-wide is pretty common. A use-case is
consolidating a pile of underused non-performance-critical servers into
one physical machine with a lot of VMs. It doesn't take much load to
cause a dhcp request to the dhcp server to steal a cpu away from the
mysql server while it holds a lock...
I'll mail out my patches so we can have a more concrete discussion shortly.
J
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