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From:   Dan Williams <dan.j.williams@intel.com>
Date:   Wed, 23 Feb 2022 13:17:07 -0800
Message-ID: <CAPcyv4jCeweE3A90bP-xUkM9pNQw=XdsFxvFye4=bVRNKWwHKQ@mail.gmail.com>
Subject: Re: [PATCH v6 0/4] Add perf interface to expose nvdimm
To:     Kajol Jain <kjain@linux.ibm.com>
Cc:     Michael Ellerman <mpe@ellerman.id.au>,
        linuxppc-dev <linuxppc-dev@lists.ozlabs.org>,
        Linux NVDIMM <nvdimm@lists.linux.dev>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        "Weiny, Ira" <ira.weiny@intel.com>,
        Vishal L Verma <vishal.l.verma@intel.com>,
        Santosh Sivaraj <santosh@fossix.org>, maddy@linux.ibm.com,
        rnsastry@linux.ibm.com,
        "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>,
        atrajeev@linux.vnet.ibm.com, Vaibhav Jain <vaibhav@linux.ibm.com>,
        Thomas Gleixner <tglx@linutronix.de>
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On Wed, Feb 23, 2022 at 11:07 AM Dan Williams <dan.j.williams@intel.com> wrote:
>
> On Fri, Feb 18, 2022 at 10:06 AM Dan Williams <dan.j.williams@intel.com> wrote:
> >
> > On Thu, Feb 17, 2022 at 8:34 AM Kajol Jain <kjain@linux.ibm.com> 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.

There's still time for the tags from:

"Madhavan Srinivasan"
"Nageswara R Sastry"

...to be reapplied, but I'll go ahead with pushing this to Linux-next
in the meantime.