why in timer mode on Xeon without SMP compiled kernel

[Yaoping R. <yruan@CS.Princeton.EDU>]

Hi,
I wanted to measure different events on a P4 Xeon box. I'd like to
get the performance of a single processor, not even with Hyper-threading
enabled. But when I specified an event, opcontrol complains:
"
You cannot specify any performance counter events
because OProfile is in timer mode.
"
This is happening on Linxu 2.6.x kernel.

Is this a bug or unavoidable? While with SMP enabled kernel, everything
just works great.

-Yaoping