Stratos Karafotis posted a patch for the Intel P-State code today that changes the calculation method for the next pstate. Stratos wrote on the mailing list, "Currently the driver calculates the next pstate proportional to core_busy factor and reverse proportional to current pstate. Change the above method and calculate the next pstate independently of current pstate."
Using a Core i7 3770, this kernel developer tested his P-State findings using the Phoronix Test Suite. He found that the kernel compilation performance was faster by about 1.5% in our benchmark. The overall test time was reduced by about 2.6% while the total energy consumption during a test iteration was lower by about 0.35%.
Let's hope this tuning work will continue and we'll see better performance out of the P-State driver for modern hardware with the Linux 3.16 kernel. Our benchmarks of all the Linux 3.15 kernel changes are forthcoming now that the code for this kernel cycle is starting to stabilize.