Hello, everyone:
     My platform is intel westmere (single socket) . The cpu is core i3. the OS kernel is linux 2.6.31. However, I encounter the following errors when I run the syst_smpl program,
the error is :
    syst_smpl: can not attach the events PERF_COUNT_HW_CPU_CYCLES: invalid parameters.
    The task_smpl program is the same error as the syst_smpl.
    The errors was occured at the call point of  the function of perf_event_open() in setup_cup()..
     I found that the error occures due to the statement fds[i].hw.watermark = 1;",  The error disappeared
 when the statement was commented.
   I want to know  the reason of the errors. Anyone can response me ?
  However, the same version of libpfm4.  I test it on another platform, which is Quad-Core AMD Opteron(tm) Processor 2378. The OS is linux AS5(2.6.34).  libpfm4 works properly.   
how about your suggestion?
Thanks in advance!