For some reason Oprofile (0.9.6) on my CentOS (5.6) box with updated kernel version 18.104.22.168 (needed for using kernel-mode Click) doesn’t see the performance counters (i.e. /dev/oprofile/cpu_type is ‘timer’). If I boot the machine up with the original kernel (i.e. 2.6.18-238.el5) /dev/oprofile/cpu_type gives me ‘i386/arch_perfmon’ and I can simply set events to count.
The newer kernel config has the same APIC options as the ‘original’ one and I even boot the machine up with the ‘lapic’ boot option, but still nothing.
By the way, I’ve got the newer 6-core Intel Nehalem (Westmere) X5670 CPUs if it matters.
Any idea of what might cause this issue or suggestion as how to resolve it would be greatly appreciated.