Hi 

By executing kernbench on 2.6.30-rc1 we observed there is a performance
regression in 2.6.30-rc1. Then git-bisect was done between v2.6.29 and
v2.6.30-rc5, after 13 iterations identified the attached patch is
causing regression.

Performance data of 2.6.29 without applying the attached patch.
param-version
testname
elapsed-avg
elapsed-std
2.6.29'
pm_kernbench.Version-none-threads=2-sched_mc=2
             221.1
              0.81
2.6.29'
pm_kernbench.Version-none-threads=4-sched_mc=0
            115.09
               0.6
2.6.29'
pm_kernbench.Version-none-threads=4-sched_mc=2
            109.05
              0.25
2.6.29'
pm_kernbench.Version-none-threads=8-sched_mc=2
              60.4
              0.38
2.6.29'
pm_kernbench.Version-none-threads=8-sched_mc=0
             65.23
              0.34
2.6.29'
pm_kernbench.Version-none-threads=2-sched_mc=0
            231.61
              0.59

Performance data of 2.6.29 after applying the attached patch.
param-version
testname
elapsed-avg
elapsed-std
2.6.29'
pm_kernbench.Version-thir-bisect-threads=2-sched_mc=0
            203.77
              0.48
2.6.29'
pm_kernbench.Version-thir-bisect-threads=8-sched_mc=0
             64.38
              0.25
2.6.29'
pm_kernbench.Version-thir-bisect-threads=4-sched_mc=0
            102.46
               0.1
2.6.29'
pm_kernbench.Version-thir-bisect-threads=8-sched_mc=2
             59.94
              0.46
2.6.29'
pm_kernbench.Version-thir-bisect-threads=4-sched_mc=2
            106.84
              0.28
2.6.29'
pm_kernbench.Version-thir-bisect-threads=2-sched_mc=2
            199.44
              0.44

Performance issue here is when sched_mc_power_savings is set 2 and
kernbench is triggered with 4 threads the value of 'elapsed time' is
more then sched_mc_power_savings is set to 0. Expectation is elapsed
time should be less when sched_mc_power_savings set 2 compared to
sched_mc_power_savings set to 0.

Regds
Poornima