Re: oprofile using timer interrupts on dual xeon / kernel 2.6.7 - why?

[William C. <wc...@re...>]

Ulrich Becker wrote:
> Hi,
> 
> we are using oprofile on two dualprocessor Xeon servers, the first is a HP
> DL140, the other one is a server built around an Intel SE7501WV2 board. Both are
> booted from the network and use the same kernel (2.6.7 SMP) and software, both
> work fine. The strange thing is, on the DL140 performance counters are used,
> whereas on the Intel SE7501WV2 oprofile falls back to timer mode. Any idea what
> might be the reason for not using performance counters on the SE7501WV2 or how
> to debug this? I am using oprofile 0.8.2.
> 
> Thanks
> Uli

The most likely guess is the oprofile is unable to identify the cpus. If 
oprofile is unable to identify the cpus as ones with performance 
monitoring hardware it can identify, OProfile falls back on the timer 
interrupt mechanism. What is the output of "cat /proc/cpuinfo" for the 
two machines?

-Will