100% cpu usage with no database load

Hello.

I have Percona Server 5.5.24 on a Centos 6 server, installed from percona yum repository, and I noticed that suddenly mysqld started consuming 100% CPU.
There is nothing shown in the processlist, in fact, this issue remains even if I disconnect database from all client applications.
I set up a slave on another server for backups, and it is affected with the same issue.
Also I noticed a high number of timer0 and timer1 interrupts that coincide with cpu load increase. Graph is attached.

…here’s the graph of CPU usage

You haven’t restarted mysqld? Look at ‘show innodb status’, maybe you can see which background process is busy. Also try if you can get a trace.