Commit 4d5a7680 authored by Robin Murphy's avatar Robin Murphy Committed by Will Deacon
Browse files

perf: Add driver for Arm NI-700 interconnect PMU 



The Arm NI-700 Network-on-Chip Interconnect has a relatively
straightforward design with a hierarchy of voltage, power, and clock
domains, where each clock domain then contains a number of interface
units and a PMU which can monitor events thereon. As such, it begets a
relatively straightforward driver to interface those PMUs with perf.

Even more so than with arm-cmn, users will require detailed knowledge of
the wider system topology in order to meaningfully analyse anything,
since the interconnect itself cannot know what lies beyond the boundary
of each inscrutably-numbered interface. Given that, for now they are
also expected to refer to the NI-700 documentation for the relevant
event IDs to provide as well. An identifier is implemented so we can
come back and add jevents if anyone really wants to.

Signed-off-by: default avatarRobin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/9933058d0ab8138c78a61cd6852ea5d5ff48e393.1725470837.git.robin.murphy@arm.com


Signed-off-by: default avatarWill Deacon <will@kernel.org>
parent abbe74dd

Documentation/admin-guide/perf/arm-ni.rst

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====================================

Arm Network-on Chip Interconnect PMU

====================================



NI-700 and friends implement a distinct PMU for each clock domain within the

interconnect. Correspondingly, the driver exposes multiple PMU devices named

arm_ni_<x>_cd_<y>, where <x> is an (arbitrary) instance identifier and <y> is

the clock domain ID within that particular instance. If multiple NI instances

exist within a system, the PMU devices can be correlated with the underlying

hardware instance via sysfs parentage.



Each PMU exposes base event aliases for the interface types present in its clock

domain. These require qualifying with the "eventid" and "nodeid" parameters

to specify the event code to count and the interface at which to count it

(per the configured hardware ID as reflected in the xxNI_NODE_INFO register).

The exception is the "cycles" alias for the PMU cycle counter, which is encoded

with the PMU node type and needs no further qualification.

Documentation/admin-guide/perf/index.rst

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@@ -16,6 +16,7 @@ Performance monitor support 
   starfive_starlink_pmu

   arm-ccn

   arm-cmn

   arm-ni

   xgene-pmu

   arm_dsu_pmu

   thunderx2-pmu

drivers/perf/Kconfig

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@@ -48,6 +48,13 @@ config ARM_CMN 
	  Support for PMU events monitoring on the Arm CMN-600 Coherent Mesh

	  Network interconnect.



config ARM_NI

	tristate "Arm NI-700 PMU support"

	depends on ARM64 || COMPILE_TEST

	help

	  Support for PMU events monitoring on the Arm NI-700 Network-on-Chip

	  interconnect and family.



config ARM_PMU

	depends on ARM || ARM64

	bool "ARM PMU framework"

drivers/perf/Makefile

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@@ -3,6 +3,7 @@ obj-$(CONFIG_ARM_CCI_PMU) += arm-cci.o 
obj-$(CONFIG_ARM_CCN) += arm-ccn.o

obj-$(CONFIG_ARM_CMN) += arm-cmn.o

obj-$(CONFIG_ARM_DSU_PMU) += arm_dsu_pmu.o

obj-$(CONFIG_ARM_NI) += arm-ni.o

obj-$(CONFIG_ARM_PMU) += arm_pmu.o arm_pmu_platform.o

obj-$(CONFIG_ARM_PMU_ACPI) += arm_pmu_acpi.o

obj-$(CONFIG_ARM_PMUV3) += arm_pmuv3.o

drivers/perf/arm-ni.c

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