High volume of calls to _spin_unlock_irqrestore causing high CPU usage
Issue
- A system is reporting high CPU usage on an application.
- "perf" output shows that
_spin_unlock_irqrestoreis consuming 20% of the processing time. - top and ps show a large percentage of time spent in %sys for a process.
Environment
- Red Hat Enterprise Linux 6 - x86 and x86-64 architecture.
- VMWare ESX 5.0.x or earlier.
- Performance monitoring tools using hardware counters (oprofile or perf)
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