Level2CacheLoadMiss Performance Impact = ((2ndlevel cache load misses retired *(15*(ProcessorSpeed/BusSpeed)))/Clockticks)*100
Where the constant "10" or "15" came from?
Another good question! If you look in the online help for a topic title "About Counter Interpretation", you will see this sentence:
"The knowledge and advice in this section was developed from the experience of Intel's performance engineers."
In general, the constants were derived by Intel engineers doing performance tuning. I'm sorry that it is not easier to locate this info.