Re: [Patch 0/1] HW-BKPT: Allow per-cpu kernel-space Hardware Breakpoint requests

Ingo Molnar
2009-08-21T14:28:38Z

* K.Prasad <prasad@linux.vnet.ibm.com> wrote:

> > Providing those would let us build a pmu struct on top of this
> > high level API, hopefully.

Note that there's a PMU struct already in
arch/x86/kernel/cpu/perf_counter.c. Could debug-register ops be
tacked on to it?

> > All that would be a benefit in both sides. It avoids us building
> > a low level PMU that reinvent the wheel, ie: the hardware
> > breakpoints API handles a lot of things both in arch and core
> > sides (debug register setting tricks with dr7 and co, cpu
> > hotplug, kexec, etc...). In the bp API it brings more power
> > (register switching only if needed, per cpu support, clone
> > inheritance support, etc...)
> >
> > And in the end we have a pmu (which unifies the control of this
> > profiling unit through a well established and known object for
> > perfcounter) controlled by a high level API that could also
> > benefit to other debugging subsystems.
> >
> > What do you think? It would be also nice to have Peter's and
> > Ingo opinion about it, to be sure we are not going in the wrong
> > direction.
>
> Indeed, it will be nice to know from Ingo and Peter that we are
> heading right.

If you do this proper perfcounters integration then i'm certainly
happy.

Ingo