Messages in this thread | | | Date | Wed, 26 Aug 2009 11:16:42 +0200 | From | Ingo Molnar <> | Subject | Re: [Patch 0/1] HW-BKPT: Allow per-cpu kernel-space Hardware Breakpoint requests |
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* Frederic Weisbecker <fweisbec@gmail.com> wrote:
> On Fri, Aug 21, 2009 at 04:28:11PM +0200, Ingo Molnar wrote: > > > > * 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? > > No, we don't need to build an arch level pmu since the BP api > already handles the arch abstraction (or well, it is planned to). > > Instead, what we need is a core pmu that relies on the BP api. > Such pmu will be allocated dynamically while creating a hardware > breakpoint counter.
i'm not convinced at all we need all that layering of perfcounters->pmu->BP. Why not add BP support to the PMU abstraction and be done with it?
That way we get hardware breakpoints via 'pinned, exclusive, per cpu hw-breakpoint counters' for example and kernel/hw-breakpoint.c can go away altogether.
kernel/perf_counter.c already handles scheduling, conflict resolution, enumeration, syscall exposure and more.
Hm?
Ingo
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