Hi, I have a question related to hardware prefetcher events on Intel Xeon processor with the below configuration. $ uname -a Linux 2.6.34-gentoo-r1 #2 SMP Mon Feb 20 12:07:35 CST 2012 x86_64 Intel Xeon CPU E5520 @ 2.27GHz GenuineIntel GNU/Linux I am trying to count the number of hardware prefetch events (a.k.a. L1D_PREFETCH:REQUESTS perfmon2 event), before and after disabling hardware prefetching using BIOS. I have followed the steps mentioned in the below link to disable h/w prefetching in BIOS. http://software.intel.com/en-us/articles/optimizing-application-performa... However even after disabling the h/w prefetching, I don't see it is having any effect on prefetching event L1D_PREFETCH:REQUESTS. I had posted this query on perfmon2 group, and I was told that since the processor E5520 is not a Core micro-architecture but Nehalem-EP the technique above to disable HW prefetcher does not apply. So my question is what is the correct way to disable hardware prefetching on this processor. PS:Kindly point me to the right forum where this question can be answered, if this is not the right place. Regards, Ram Graduate student University of Houston