mysql high cpu usage (no have slow queries)
Somebody is trying to hack your server using bots (all these log entries are login attempts). To be honest I see the same atempts in my logs all the time. To check if this is the source of your server overload (I am not sure...) try to restrict network connections to mySQL: uncomment this line in your mysqld.cnf
bind-address    = 127.0.0.1

Then restart your mySQL and check the load.