Clocksource calibration issues on E5530

Issue

• Dell clusters with E5530 processors are suffering from hard to pin down problems since being moved from 6.2 to 6.4
• It has been found that machines afflicted share a common trait which unaffected machines do not.
• It appears that the processor clock calibration loop is interrupted causing a miscalibration of the auxiliary processor.
• This is characterized by the bogo-mips for the processor being unreasonably incorrect.
• For example, on a normally functioning node all the processor's bogomips will be near 4800 while on a malfunctioning node the processors will be variously either around 2000, or around 6000