Documentation/admin-guide/perf/nvidia-tegra241-pmu.rst

Source file repositories/reference/linux-study-clean/Documentation/admin-guide/perf/nvidia-tegra241-pmu.rst

File Facts

System
Linux kernel
Corpus path
Documentation/admin-guide/perf/nvidia-tegra241-pmu.rst
Extension
.rst
Size
14326 bytes
Lines
334
Domain
Support Tooling And Documentation
Bucket
Documentation
Inferred role
Support Tooling And Documentation: documentation
Status
atlas-only

Why This File Exists

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

Dependency Surface

Detected Declarations

Annotated Snippet

============================================================
NVIDIA Tegra241 SoC Uncore Performance Monitoring Unit (PMU)
============================================================

The NVIDIA Tegra241 SoC includes various system PMUs to measure key performance
metrics like memory bandwidth, latency, and utilization:

* Scalable Coherency Fabric (SCF)
* NVLink-C2C0
* NVLink-C2C1
* CNVLink
* PCIE

PMU Driver
----------

The PMUs in this document are based on ARM CoreSight PMU Architecture as
described in document: ARM IHI 0091. Since this is a standard architecture, the
PMUs are managed by a common driver "arm-cs-arch-pmu". This driver describes
the available events and configuration of each PMU in sysfs. Please see the
sections below to get the sysfs path of each PMU. Like other uncore PMU drivers,
the driver provides "cpumask" sysfs attribute to show the CPU id used to handle
the PMU event. There is also "associated_cpus" sysfs attribute, which contains a
list of CPUs associated with the PMU instance.

.. _SCF_PMU_Section:

SCF PMU
-------

The SCF PMU monitors system level cache events, CPU traffic, and
strongly-ordered (SO) PCIE write traffic to local/remote memory. Please see
:ref:`NVIDIA_Uncore_PMU_Traffic_Coverage_Section` for more info about the PMU
traffic coverage.

The events and configuration options of this PMU device are described in sysfs,
see /sys/bus/event_source/devices/nvidia_scf_pmu_<socket-id>.

Example usage:

* Count event id 0x0 in socket 0::

   perf stat -a -e nvidia_scf_pmu_0/event=0x0/

* Count event id 0x0 in socket 1::

   perf stat -a -e nvidia_scf_pmu_1/event=0x0/

NVLink-C2C0 PMU
--------------------

The NVLink-C2C0 PMU monitors incoming traffic from a GPU/CPU connected with
NVLink-C2C (Chip-2-Chip) interconnect. The type of traffic captured by this PMU
varies dependent on the chip configuration:

* NVIDIA Grace Hopper Superchip: Hopper GPU is connected with Grace SoC.

  In this config, the PMU captures GPU ATS translated or EGM traffic from the GPU.

* NVIDIA Grace CPU Superchip: two Grace CPU SoCs are connected.

  In this config, the PMU captures read and relaxed ordered (RO) writes from
  PCIE device of the remote SoC.

Please see :ref:`NVIDIA_Uncore_PMU_Traffic_Coverage_Section` for more info about
the PMU traffic coverage.

The events and configuration options of this PMU device are described in sysfs,
see /sys/bus/event_source/devices/nvidia_nvlink_c2c0_pmu_<socket-id>.

Annotation

Implementation Notes