linux/Documentation/ABI/testing/sysfs-bus-event_source-devices-hv_gpci
Kajol Jain 09b791d955 powerpc/hv-gpci: Add sysfs files inside hv-gpci device to show cpumask
Patch here adds a cpumask attr to hv_gpci pmu along with ABI documentation.

Primary use to expose the cpumask is for the perf tool which has the
capability to parse the driver sysfs folder and understand the
cpumask file. Having cpumask file will reduce the number of perf command
line parameters (will avoid "-C" option in the perf tool
command line). It can also notify the user which is
the current cpu used to retrieve the counter data.

command:# cat /sys/devices/hv_gpci/cpumask
0

Signed-off-by: Kajol Jain <kjain@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201003074943.338618-5-kjain@linux.ibm.com
2020-10-07 22:34:49 +11:00

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What: /sys/bus/event_source/devices/hv_gpci/format
Date: September 2020
Contact: Linux on PowerPC Developer List <linuxppc-dev@lists.ozlabs.org>
Description: Read-only. 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. All supported attributes are listed
below.
counter_info_version = "config:16-23"
length = "config:24-31"
partition_id = "config:32-63"
request = "config:0-31"
sibling_part_id = "config:32-63"
hw_chip_id = "config:32-63"
offset = "config:32-63"
phys_processor_idx = "config:32-63"
secondary_index = "config:0-15"
starting_index = "config:32-63"
For example,
processor_core_utilization_instructions_completed = "request=0x94,
phys_processor_idx=?,counter_info_version=0x8,
length=8,offset=0x18"
In this event, '?' after phys_processor_idx specifies this value
this value will be provided by user while running this event.
What: /sys/bus/event_source/devices/hv_gpci/interface/collect_privileged
Date: February 2014
Contact: Linux on PowerPC Developer List <linuxppc-dev@lists.ozlabs.org>
Description:
'0' if the hypervisor is configured to forbid access to event
counters being accumulated by other guests and to physical
domain event counters.
'1' if that access is allowed.
What: /sys/bus/event_source/devices/hv_gpci/interface/ga
Date: February 2014
Contact: Linux on PowerPC Developer List <linuxppc-dev@lists.ozlabs.org>
Description:
0 or 1. Indicates whether we have access to "GA" events (listed
in arch/powerpc/perf/hv-gpci.h).
What: /sys/bus/event_source/devices/hv_gpci/interface/expanded
Date: February 2014
Contact: Linux on PowerPC Developer List <linuxppc-dev@lists.ozlabs.org>
Description:
0 or 1. Indicates whether we have access to "EXPANDED" events (listed
in arch/powerpc/perf/hv-gpci.h).
What: /sys/bus/event_source/devices/hv_gpci/interface/lab
Date: February 2014
Contact: Linux on PowerPC Developer List <linuxppc-dev@lists.ozlabs.org>
Description:
0 or 1. Indicates whether we have access to "LAB" events (listed
in arch/powerpc/perf/hv-gpci.h).
What: /sys/bus/event_source/devices/hv_gpci/interface/version
Date: February 2014
Contact: Linux on PowerPC Developer List <linuxppc-dev@lists.ozlabs.org>
Description:
A number indicating the version of the gpci interface that the
hypervisor reports supporting.
What: /sys/bus/event_source/devices/hv_gpci/interface/kernel_version
Date: February 2014
Contact: Linux on PowerPC Developer List <linuxppc-dev@lists.ozlabs.org>
Description:
A number indicating the latest version of the gpci interface
that the kernel is aware of.
What: /sys/devices/hv_gpci/cpumask
Date: October 2020
Contact: Linux on PowerPC Developer List <linuxppc-dev@lists.ozlabs.org>
Description: read only
This sysfs file exposes the cpumask which is designated to make
HCALLs to retrieve hv-gpci pmu event counter data.