Ticket to a tarpit*
One Line Summary
Ticket spinlocks have surprisingly bad behaviour in a VM
Ticket spinlocks have some very nice properties – in particular guaranteed FIFO ordering in the face of hardware cache-coherency protocol madness.
But those very properties have a dark side in virtual environments, and some kind of paravirtualization is a must.
Virtualization, kernel, spinlocks, paravirtualization
I’ve been hacking on Linux since pre-1.0 and Xen for the last couple of years.