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kernel: Package power limit notification

I get this frequently in syslog:
Dec 28 11:44:00 kernel: CPU0: Package power limit notification (total events = 355)
Dec 28 11:44:00 kernel: CPU2: Package power limit notification (total events = 355)
Dec 28 11:44:00 kernel: CPU1: Package power limit notification (total events = 355)
Dec 28 11:44:00 kernel: CPU3: Package power limit notification (total events = 355)
Dec 28 11:44:00 kernel: CPU1: Package power limit normal
Dec 28 11:44:00 kernel: CPU0: Package power limit normal
Dec 28 11:44:00 kernel: CPU2: Package power limit normal
Dec 28 11:44:00 kernel: CPU3: Package power limit normal
Usually when Firefox uses a lot of CPU.  There are many forum posts regarding these messages. But there is nothing to worry about. A bit of background.

These messages are logged by the kernel, in the file: arch/x86/kernel/cpu/mcheck/therm_throt.c
This feature is enabled by the X86_MCE_INTEL config option, which is located under:
Processor type and features
[*] Machine Check / overheating reporting
[*]   Intel MCE features
In dmesg it shows this message, during boot, if the kernel decided to handle thermal interrupts (and not the BIOS):
CPU0: Thermal monitoring enabled (TM1)

So the kernel now gets thermal interrupts from your CPU when certain temperature limits are crossed. The kernel's thermal and power management then decides what to do to decrease the temperature. This is normal operation and nothing to worry about.



posted on 2012-12-28 12:17 UTC in Code | 0 comments | permalink