Re: [PATCH v6 0/4] Add perf interface to expose nvdimm

[Dan Williams]

On Fri, Feb 18, 2022 at 10:06 AM Dan Williams <dan.j.williams@xxxxxxxxx> wrote:
>
> On Thu, Feb 17, 2022 at 8:34 AM Kajol Jain <kjain@xxxxxxxxxxxxx> wrote:
> >
> > Patchset adds performance stats reporting support for nvdimm.
> > Added interface includes support for pmu register/unregister
> > functions. A structure is added called nvdimm_pmu to be used for
> > adding arch/platform specific data such as cpumask, nvdimm device
> > pointer and pmu event functions like event_init/add/read/del.
> > User could use the standard perf tool to access perf events
> > exposed via pmu.
> >
> > Interface also defines supported event list, config fields for the
> > event attributes and their corresponding bit values which are exported
> > via sysfs. Patch 3 exposes IBM pseries platform nmem* device
> > performance stats using this interface.
> >
> > Result from power9 pseries lpar with 2 nvdimm device:
> >
> > Ex: List all event by perf list
> >
> > command:# perf list nmem
> >
> >   nmem0/cache_rh_cnt/                                [Kernel PMU event]
> >   nmem0/cache_wh_cnt/                                [Kernel PMU event]
> >   nmem0/cri_res_util/                                [Kernel PMU event]
> >   nmem0/ctl_res_cnt/                                 [Kernel PMU event]
> >   nmem0/ctl_res_tm/                                  [Kernel PMU event]
> >   nmem0/fast_w_cnt/                                  [Kernel PMU event]
> >   nmem0/host_l_cnt/                                  [Kernel PMU event]
> >   nmem0/host_l_dur/                                  [Kernel PMU event]
> >   nmem0/host_s_cnt/                                  [Kernel PMU event]
> >   nmem0/host_s_dur/                                  [Kernel PMU event]
> >   nmem0/med_r_cnt/                                   [Kernel PMU event]
> >   nmem0/med_r_dur/                                   [Kernel PMU event]
> >   nmem0/med_w_cnt/                                   [Kernel PMU event]
> >   nmem0/med_w_dur/                                   [Kernel PMU event]
> >   nmem0/mem_life/                                    [Kernel PMU event]
> >   nmem0/poweron_secs/                                [Kernel PMU event]
> >   ...
> >   nmem1/mem_life/                                    [Kernel PMU event]
> >   nmem1/poweron_secs/                                [Kernel PMU event]
> >
> > Patch1:
> >         Introduces the nvdimm_pmu structure
> > Patch2:
> >         Adds common interface to add arch/platform specific data
> >         includes nvdimm device pointer, pmu data along with
> >         pmu event functions. It also defines supported event list
> >         and adds attribute groups for format, events and cpumask.
> >         It also adds code for cpu hotplug support.
> > Patch3:
> >         Add code in arch/powerpc/platform/pseries/papr_scm.c to expose
> >         nmem* pmu. It fills in the nvdimm_pmu structure with pmu name,
> >         capabilities, cpumask and event functions and then registers
> >         the pmu by adding callbacks to register_nvdimm_pmu.
> > Patch4:
> >         Sysfs documentation patch
> >
> > Changelog
> > ---
> > Resend v5 -> v6
> > - No logic change, just a rebase to latest upstream and
> >   tested the patchset.
> >
> > - Link to the patchset Resend v5: https://lkml.org/lkml/2021/11/15/3979
> >
> > v5 -> Resend v5
> > - Resend the patchset
> >
> > - Link to the patchset v5: https://lkml.org/lkml/2021/9/28/643
> >
> > v4 -> v5:
> > - Remove multiple variables defined in nvdimm_pmu structure include
> >   name and pmu functions(event_int/add/del/read) as they are just
> >   used to copy them again in pmu variable. Now we are directly doing
> >   this step in arch specific code as suggested by Dan Williams.
> >
> > - Remove attribute group field from nvdimm pmu structure and
> >   defined these attribute groups in common interface which
> >   includes format, event list along with cpumask as suggested by
> >   Dan Williams.
> >   Since we added static defination for attrbute groups needed in
> >   common interface, removes corresponding code from papr.
> >
> > - Add nvdimm pmu event list with event codes in the common interface.
> >
> > - Remove Acked-by/Reviewed-by/Tested-by tags as code is refactored
> >   to handle review comments from Dan.
>
> I don't think review comments should invalidate the Acked-by tags in
> this case. Nothing fundamentally changed in the approach, and I would
> like to have the perf ack before taking this through the nvdimm tree.
>
> Otherwise this looks good to me.
>
> Peter, might you have a chance to re-Ack this series, or any concerns
> about me retrieving those Acks from the previous postings?

Reached Peter offline and he refreshed his Acked-by.