this is based off the 0.9.2.1rc1 core_2 events file...
the default mask for L2_RQSTS is 0xcf -- this double
counts references because oprofile is generally running
on all cores. the default should probably be 0x4f.
i've verified this with a multithreaded microbenchmark
issuing random walks on all processors and the results
for 0x4f are more in-line with what i'd expect.
i've attached a patch to correct this and several other