something really weird is going on

[gauthamt]

I'm running the same toy benchmark on a Linux box and am running my collector on a Windows machine. On my first run I collect the 'Instructions Retired' and 'L2 Cache miss retired' parameters. Then in my second run I collect 'Instructions Retired','L2 Cache miss retired' and 'DTLB miss retired'. Look at the sampling run outputs below.

As you can c the first run does not collect any L2 misses whereas the 2nd run has a L2 load miss rate /instruction (retired) of 67%. I verified to c that both the activites had the same number of instructions retired (appr 12samples * 1.999.000 (sample intervel)).

1st Activity---
Mon Apr 14 14:48:51 2003 10.32.44.40 (Run 1) The Sampling Collector is collecting samples based on the following event(s): Instructions Retired, Clockticks.
Mon Apr 14 14:48:55 2003 10.32.44.40 (Run 1) Sampling data was successfully collected.
Mon Apr 14 14:48:55 2003 10.32.44.40 (Run 2) The Sampling Collector is collecting samples based on the following event(s): 2nd Level Cache Load Misses Retired.
Mon Apr 14 14:48:59 2003 10.32.44.40 (Run 2) The Sampling Collector failed to collect data because the selected event(s) did not occur.

2nd Activity
Mon Apr 14 14:50:52 2003 10.32.44.40 (Run 1) The Sampling Collector is collecting samples based on the following event(s): DTLB Load and Store Misses Retired.
Mon Apr 14 14:50:56 2003 10.32.44.40 (Run 1) The Sampling Collector failed to collect data because the selected event(s) did not occur.
Mon Apr 14 14:50:56 2003 10.32.44.40 (Run 2) The Sampling Collector is collecting samples based on the following event(s): 2nd Level Cache Load Misses Retired.
Mon Apr 14 14:51:00 2003 10.32.44.40 (Run 2) Sampling data was successfully collected.
Mon Apr 14 14:51:00 2003 10.32.44.40 (Run 3) The Sampling Collector is collecting samples based on the following event(s): Instructions Retired.
Mon Apr 14 14:51:04 2003 10.32.44.40 (Run 3) Sampling data was successfully collected.