Thread (16 messages) 16 messages, 3 authors, 2021-09-15

Re: [RESEND PATCH v4 4/4] powerpc/papr_scm: Document papr_scm sysfs event format entries

From: Dan Williams <hidden>
Date: 2021-09-08 01:04:01
Also in: lkml, nvdimm

On Thu, Sep 2, 2021 at 10:11 PM Kajol Jain [off-list ref] wrote:
quoted hunk ↗ jump to hunk
Details is added for the event, cpumask and format attributes
in the ABI documentation.

Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Tested-by: Nageswara R Sastry <redacted>
Signed-off-by: Kajol Jain <redacted>
---
 Documentation/ABI/testing/sysfs-bus-papr-pmem | 31 +++++++++++++++++++
 1 file changed, 31 insertions(+)
diff --git a/Documentation/ABI/testing/sysfs-bus-papr-pmem b/Documentation/ABI/testing/sysfs-bus-papr-pmem
index 95254cec92bf..4d86252448f8 100644
--- a/Documentation/ABI/testing/sysfs-bus-papr-pmem
+++ b/Documentation/ABI/testing/sysfs-bus-papr-pmem
@@ -61,3 +61,34 @@ Description:
                * "CchRHCnt" : Cache Read Hit Count
                * "CchWHCnt" : Cache Write Hit Count
                * "FastWCnt" : Fast Write Count
+
+What:          /sys/devices/nmemX/format
+Date:          June 2021
+Contact:       linuxppc-dev <linuxppc-dev@lists.ozlabs.org>, nvdimm@lists.linux.dev,
+Description:   (RO) Attribute group to describe the magic bits
+                that go into perf_event_attr.config for a particular pmu.
+                (See ABI/testing/sysfs-bus-event_source-devices-format).
+
+                Each attribute under this group defines a bit range of the
+                perf_event_attr.config. Supported attribute is listed
+                below::
+
+                   event  = "config:0-4"  - event ID
+
+               For example::
+                   noopstat = "event=0x1"
+
+What:          /sys/devices/nmemX/events
That's not a valid sysfs path. Did you mean /sys/bus/nd/devices/nmemX?
+Date:          June 2021
+Contact:       linuxppc-dev [off-list ref], nvdimm@lists.linux.dev,
+Description:    (RO) Attribute group to describe performance monitoring
+                events specific to papr-scm. Each attribute in this group describes
+                a single performance monitoring event supported by this nvdimm pmu.
+                The name of the file is the name of the event.
+                (See ABI/testing/sysfs-bus-event_source-devices-events).
Given these events are in the generic namespace the ABI documentation
should be generic as well. So I think move these entries to
Documentation/ABI/testing/sysfs-bus-nvdimm directly.

You can still mention papr-scm, but I would expect something like:

What:           /sys/bus/nd/devices/nmemX/events
Date:           September 2021
KernelVersion:  5.16
Contact:        Kajol Jain [off-list ref]
Description:
                (RO) Attribute group to describe performance monitoring events
                for the nvdimm memory device. Each attribute in this group
                describes a single performance monitoring event supported by
                this nvdimm pmu.  The name of the file is the name of the event.
                (See ABI/testing/sysfs-bus-event_source-devices-events). A
                listing of the events supported by a given nvdimm provider type
                can be found in Documentation/driver-api/nvdimm/$provider, for
                example: Documentation/driver-api/nvdimm/papr-scm.


+
+What:          /sys/devices/nmemX/cpumask
+Date:          June 2021
+Contact:       linuxppc-dev [off-list ref], nvdimm@lists.linux.dev,
+Description:   (RO) This sysfs file exposes the cpumask which is designated to make
+                HCALLs to retrieve nvdimm pmu event counter data.
Seems this one would be provider generic, so no need to refer to PPC
specific concepts like HCALLs.
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