Re: Oprofile : need to adjust PC by 16 bytes

From: Andi Kleen
Date: Sat Nov 15 2008 - 13:27:22 EST


On Sat, Nov 15, 2008 at 05:30:58PM +0100, Eric Dumazet wrote:
> Andi Kleen a écrit :
> >>>And no, blindly subtracting 16 from IP is not a fix.
> >>Who mentioned a fix ? I am only giving more fuel to Intel guys so they
> >>hopefully can give us a working oprofile.
> >
> >You would need to implement PEBS support to avoid that problem. But it's a
> >big
> >task. perfmon2 implements it already.
> >
>
> Thanks for the information.
>
> Hum, so I grabbed perfmon2 git tree, installed various tools...
>
> I am quite new to pfmon and tried :
>
> # pfmon --system-wide
> sizeof=64 44
> <press ENTER to stop session>
>
> Then started "tbench 8", and got a kernel panic after 6 seconds.
>
>
> I was using oprofile like this
>
> opcontrol --vmlinux=/path/vmlinux --start
> // doing some benchmarking...
> opreport -l vmlinux | head -n 40
>
>
> What would be a working equivalent for perfmon2 based tools ?

Probably getting a perfmon tree that works. I guess Stephane
can help (cc'ed). Or just deal with imprecise events for now.

-Andi
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