Mine the Harvest

Ever notice boot messages like:

perf_event_intel: PEBS disabled due to CPU errata, please upgrade microcode

Linux supports applying CPU microcode updates at runtime.

Should you do so? Have microcode updates already been applied? How do you apply them?

Intel does not issue release notes with microcode, thus they are a black box. Despite not knowing precisely what fixes they contain, it seems to me applying the manufacturers intended update is likely to do more good than harm. Fortunately this is quite easy to do, especially with a 3.4 or newer kernel.

Granted, a microcode update is not going to magically grow new circuitry and upgrade your i7 to support AVX, but I’ve been interested in how all this worked for a while and so decided to dive in.

Microcode is distributed in ACSII encoded cryptographically signed binary files which are available for Download from Intel. A variety of tools exist to extract and apply updates from this file.

The following article on my wiki contains information on Intel and AMD microcode updates applicable to any Linux distribution.

http://www.timelordz.com/wiki/Microcode

Happy patching.