Re: [PATCH] perf/core: move all of the pmu devices into their own location

[Ian Rogers]

On Mon, Feb 3, 2025 at 11:05 PM Greg Kroah-Hartman
<gregkh@xxxxxxxxxxxxxxxxxxx> wrote:
>
> On Mon, Feb 03, 2025 at 11:44:13AM -0800, Ian Rogers wrote:
> > On Mon, Feb 3, 2025 at 11:25 AM Greg Kroah-Hartman
> > <gregkh@xxxxxxxxxxxxxxxxxxx> wrote:
[snip]
> > > Note, if you all don't like "pmu_bus" for the name, that's fine, please
> > > let me know and I can rename it to something else, but it should be
> > > something to get these objects out of the root sysfs directory.
> >
> > Excuse my ignorance, does the event_source bus already provide a
> > similar solution?
> > ```
> > $ ls /sys/bus/event_source/devices
> > breakpoint   i915       msr         uncore_arb     uncore_cbox_3
> > uncore_cbox_7              uprobe
> > cpu          intel_bts  power       uncore_cbox_0  uncore_cbox_4  uncore_clock
> > cstate_core  intel_pt   software    uncore_cbox_1  uncore_cbox_5
> > uncore_imc_free_running_0
> > cstate_pkg   kprobe     tracepoint  uncore_cbox_2  uncore_cbox_6
> > uncore_imc_free_running_1
> > $ ls /sys/devices
> > breakpoint   intel_pt     platform    uncore_arb     uncore_cbox_5
> >          uprobe
> > cpu          isa          pnp0        uncore_cbox_0  uncore_cbox_6
> >          virtual
> > cstate_core  kprobe       power       uncore_cbox_1  uncore_cbox_7
> > cstate_pkg   LNXSYSTM:00  software    uncore_cbox_2  uncore_clock
> > i915         msr          system      uncore_cbox_3  uncore_imc_free_running_0
> > intel_bts    pci0000:00   tracepoint  uncore_cbox_4  uncore_imc_free_running_1
> > ```
>
> Those are the exact same device structures :)
>
> Look at /sys/bus/event_source/devices/ those are symlinks back to
> /sys/devices.  In other words, that's the exact same structures, and
> the mess in /sys/devices/ with these event devices is what I am trying
> to clean up.

Thanks! Again my ignorance, why do we need pmu_bus? Could the symlinks
in event_source be the actual devices? Perhaps for temporary
compatibility some symlinks could be placed in /sys/devices?

Thanks,
Ian