-.. BSD LICENSE
- Copyright(c) 2010-2014 Intel Corporation. All rights reserved.
- All rights reserved.
-
- Redistribution and use in source and binary forms, with or without
- modification, are permitted provided that the following conditions
- are met:
-
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- notice, this list of conditions and the following disclaimer.
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- distribution.
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-
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+.. SPDX-License-Identifier: BSD-3-Clause
+ Copyright(c) 2010-2014 Intel Corporation.
Profile Your Application
========================
+The following sections describe methods of profiling DPDK applications on
+different architectures.
+
+
+Profiling on x86
+----------------
+
Intel processors provide performance counters to monitor events.
-Some tools provided by Intel can be used to profile and benchmark an application.
+Some tools provided by Intel, such as Intel® VTune™ Amplifier, can be used
+to profile and benchmark an application.
See the *VTune Performance Analyzer Essentials* publication from Intel Press for more information.
For a DPDK application, this can be done in a Linux* application environment only.
Refer to the
`Intel Performance Analysis Guide <http://software.intel.com/sites/products/collateral/hpc/vtune/performance_analysis_guide.pdf>`_
for details about application profiling.
+
+
+Profiling with VTune
+~~~~~~~~~~~~~~~~~~~~
+
+To allow VTune attaching to the DPDK application, reconfigure a DPDK build
+folder by passing ``-Dc_args=-DRTE_ETHDEV_PROFILE_WITH_VTUNE`` meson option
+and recompile the DPDK:
+
+.. code-block:: console
+
+ meson build
+ meson configure build -Dc_args=-DRTE_ETHDEV_PROFILE_WITH_VTUNE
+ ninja -C build
+
+
+Profiling on ARM64
+------------------
+
+Using Linux perf
+~~~~~~~~~~~~~~~~
+
+The ARM64 architecture provide performance counters to monitor events. The
+Linux ``perf`` tool can be used to profile and benchmark an application. In
+addition to the standard events, ``perf`` can be used to profile arm64
+specific PMU (Performance Monitor Unit) events through raw events (``-e``
+``-rXX``).
+
+For more derails refer to the
+`ARM64 specific PMU events enumeration <http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.100095_0002_04_en/way1382543438508.html>`_.
+
+
+Low-resolution generic counter
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+The default ``cntvct_el0`` based ``rte_rdtsc()`` provides a portable means to
+get a wall clock counter in user space. Typically it runs at a lower clock frequency than the CPU clock frequency.
+Cycles counted using this method should be scaled to CPU clock frequency.
+
+
+High-resolution cycle counter
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+The alternative method to enable ``rte_rdtsc()`` for a high resolution wall
+clock counter is through the ARMv8 PMU subsystem. The PMU cycle counter runs
+at CPU frequency. However, access to the PMU cycle counter from user space is
+not enabled by default in the arm64 linux kernel. It is possible to enable
+cycle counter for user space access by configuring the PMU from the privileged
+mode (kernel space).
+
+By default the ``rte_rdtsc()`` implementation uses a portable ``cntvct_el0``
+scheme.
+
+The example below shows the steps to configure the PMU based cycle counter on
+an ARMv8 machine.
+
+.. code-block:: console
+
+ git clone https://github.com/jerinjacobk/armv8_pmu_cycle_counter_el0
+ cd armv8_pmu_cycle_counter_el0
+ make
+ sudo insmod pmu_el0_cycle_counter.ko
+
+Please refer to :doc:`../linux_gsg/build_dpdk` for details on compiling DPDK with meson.
+
+.. warning::
+
+ The PMU based scheme is useful for high accuracy performance profiling with
+ ``rte_rdtsc()``. However, this method can not be used in conjunction with
+ Linux userspace profiling tools like ``perf`` as this scheme alters the PMU
+ registers state.