Arm RAN Acceleration Library 21.01 Release Note
===============================================

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Product Status
--------------

The information in this document is Final, that is for a developed product.

Web Address
-----------

https://developer.arm.com

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Contents
========

- Conventions
- Release overview
- Release contents
- Get started
- Support
- Release History

Conventions
===========

The following subsections describe conventions used in Arm documents.

Glossary
--------

The Arm Glossary is a list of terms that are used in Arm documentation, together
with definitions for those terms. The Arm Glossary does not contain terms that
are industry standard unless the Arm meaning differs from the generally accepted
meaning.

See the Arm Glossary for more information: https://developer.arm.com/glossary.

Release overview
================

Use of Arm RAN Acceleration Library is subject to the terms and conditions of
the applicable End User License Agreement (“EULA”). A copy of the EULA can be
found in the 'license_terms' folder of your product installation.

Product description
-------------------

The Arm RAN Acceleration Library (ArmRAL) contains a set of functions for
accelerating telecommunications applications such as, but not limited to, 5G
Radio Access Networks (RANs).

The Arm RAN Acceleration Library 21.01 package provides a
library that is optimized for Armv8-A AArch64-based processors.

The library provides:

  - Vector functions
  - Matrix functions
  - Lower PHY support functions
  - Upper PHY support functions
  - DU-RU Interface support functions

The library includes functions that operate on 16-bit signed integers and 32-bit
floating-point values.

Release Status
--------------

This is the 21.01 release of Arm RAN Acceleration Library.

These deliverables are being released under the terms of the agreement between
Arm and each licensee (the "Agreement"). All planned verification and
validation is complete.
The release is suitable for volume production under the terms of the Agreement.

Release contents
================

The following sub-sections describe:
- The product parts that are delivered as part of this release.
- Any changes since the previous release.
- Any known issues and limitations that exist at the time of this release.

Deliverables
------------

- Arm RAN Acceleration Library 21.01
- Release Notes (this document)
- Documentation (product documentation is available on the Arm developer
  website at:

  https://developer.arm.com/solutions/infrastructure/developer-resources/5g/ran)

  Documentation may change between product releases. For the latest
  documentation bundle, check the delivery platform.

  Arm tests its PDFs only in Adobe Acrobat and Acrobat Reader. Arm cannot
  guarantee the quality this document when used with any other PDF reader.
  A suitable file reader can be downloaded from Adobe at http://www.adobe.com

Differences from previous release
---------------------------------

The following subsections describe differences from the previous release of
Arm RAN Acceleration Library.

Additions and changes:
~~~~~~~~~~~~~~~~~~~~~~

Describes new features or components added, or any technical changes to
features or components, in this release.

- The operation of the "type" parameter in the interface for armral_solve_*
  functions has changed. Instead of specifying the equalization type using a
  parameter, you must now specify the number of subcarriers per G matrix. To
  enable this, the "type" parameter in the interface for armral_solve_*
  functions has been replaced by "num_sc_per_g". You need to update your code
  so that you pass four or six to the armral_solve_* function, instead of
  passing one or two, respectively.

- armral_solve_* functions now support equalization with a single subcarrier
  per G matrix. To enable this equalization, pass one as the value to the
  "num_sc_per_g" parameter in the armral_solve_* functions. Note that this
  type of equalization is not type-1 equalization; type-1 equalization solves
  four subcarriers per G matrix.

- Benchmarking now prints all the performance data, in addition to the median
  value. Previously, only the median value was printed. You can use the
  additional data for performing further statistical analyses.

- Benchmarking now prints the MD5 checksum of the binary being benchmarked. The
  checksum can be useful for deciding if code changes are responsible for
  performance differences, or if the performance differences are due to noise in
  the benchmark itself.

- If you attempt to configure using an old version of the GCC or Clang
  compilers, CMake now emits a warning. The warning is not an error. You can
  build with unsupported compilers, but the warning indicates that the library
  might not compile successfully.

- Improved the CRC24 performance, both in big and little-endian modes.

- The armral_cmplx_vecmul_i16_2 function now saturates intermediate values to
  operate the same as the other vector multiply functions.

- Improved the performance of armral_cmplx_vecmul_i16_2.

- Added the 'ARMRAL_ENABLE_COVERAGE' option to CMake. For more information about
  the 'ARMRAL_ENABLE_COVERAGE' option, see the README.

- Added a new 'make uninstall' target. The new 'make uninstall' target
  simplifies the uninstall process; any empty directories that were previously
  created as part of uninstallation are now removed automatically.

- Improved the performance of 9-bit and 12-bit block-float compression.

- Improved the performance of 9-bit block-float decompression.

- Improved the performance of the Pearson correlation coefficient calculation.

- Improved the performance of equalization (armral_solve_*) functions for type-2
  cases. In type-2 cases, the same equalization matrix G is used for six
  consecutive input vectors, in other words "num_sc_per_g=6". For more
  information, see the ArmRAL documentation.

- Improved the performance of FFTs that take complex Q15 input and produce
  complex Q15 output.

- Improved the performance of FFTs that take 32-bit complex float input and
  produce 32-bit complex float output.

- The equalization routines (armral_solve_*) no longer accept numbers of
  samples that are not divisible by 12 because 12 is the size of one
  resource block.

- Improved the performance of the 32-bit complex vector dot product functions:
  armral_cmplx_vecdot_i16_32bit and armral_cmplx_vecdot_i16_2_32bit.

Resolved issues:
~~~~~~~~~~~~~~~~

- 'CMAKE_C_FLAGS' and 'CMAKE_CXX_FLAGS' are no longer ignored when passed as
  environment variables to the initial CMake configure step.

- Previously, CRC24 benchmarking crashed with an assertion failure when built
  with 'CMAKE_BUILD_TYPE=Debug' because the benchmarks attempted to pass an
  invalid length. These invalid cases have been removed.

- Updated the Pearson correlation coefficient implementation to:

   * Use floating-point instead of fixed-point square root calculations. For
     large inputs, the fixed-point square root did not produce a
     correctly rounded result. Now, the implementation uses the floating point
     square root. To convert the result to the equivalent of a fixed-point
     calculation, the implementation rounds the result to the nearest integer.

   * Remove redundant bit-shifts which might cause inaccuracies for small
     coefficients.

- Benchmarking incorrectly reported the solve_type*_2x2_* and solve_type*_1x4_*
  results: the solve_type*_1x4_* results were reported as the solve_type*_2x2_*
  results, and the solve_type*_2x2_* were reported as the solve_type*_1x4_*
  results. The reporting of the function results has been corrected.

- Previously, Polar decoding modified global state as part of the operation,
  which could lead to errors if multiple threads attempted decoding
  simultaneously. The polar decoding operation no longer modifies global state.
  The function is now thread-safe.

- Previously, if the number of subcarriers was not a multiple of 24, type-1
  equalization routines (armral_solve_*) read off the end of the input G arrays.
  The issue does not affect the correctness of the operation, however, the
  memory accesses responsible for the reads off the end of the arrays have been
  fixed.

Known limitations
-----------------

There are no open technical issues at the time of this release.

Get started
===========

This section describes information to help you get started with accessing,
setting up, and using Arm RAN Acceleration Library.

Licensing information
---------------------

Use of Arm RAN Acceleration Library is subject to the terms and conditions of
the applicable End User License Agreement (“EULA”). A copy of the EULA can be
found in the 'license_terms' folder of your product installation.

You do not require a license to use this Arm RAN Acceleration Library package.

Prerequisites
-------------

The library runs on AArch64 cores, however to use the CRC functions, you
must run on a core that supports the AArch64 PMULL extension. If your machine
supports the PMULL extension, pmull is listed under the "Features" list given in
the /proc/cpuinfo file.

If any of the following tools are not already installed on your system, you
must install them before building or running Arm RAN Acceleration Library:

* A recent version of a C/C++ compiler, such as GCC. The library has been tested
  with GCC 7.1.0, 8.2.0, 9.3.0, and 10.2.0.

* A recent version of CMake (version 3.0.0, or higher).

In addition to the preceding requirements:

* To run the benchmarks, you must have the Linux utility tool 'perf' installed.

* To build a local version of the documentation, you must have Doxygen
  installed.

Download Arm RAN Acceleration Library
-------------------------------------

Arm delivers the Arm RAN Acceleration Library files through the Arm developer
website:

  https://developer.arm.com/solutions/infrastructure/developer-resources/5g/ran

Unpack the product
------------------

The following steps describe how to unpack each constituent part delivered in
this bundle:

1. Relocate the bundle file. Move the .tar.gz file to the directory you want to
   build the product in.

2. Extract the .tar.gz file contents using a tar utility:

     tar zxvf arm-ran-acceleration-library-21.01-aarch64.tar.gz

Compile the product
-------------------

To build the library, navigate to the unpacked product directory and use the
following commands:

  mkdir <build>
  cd <build>
  cmake [options] <path>
  make

Substitute:

* '<build>' with a directory name to build the library in
* '[options]' with the CMake options to use to build the library
* '<path>' with the path to the root directory of the library source.

For a list of the common CMake options that are supported, see the instructions
in the README.md file. You can find README.md in the unzipped package directory.

Directory structure:
--------------------

Shows the principal directory structure of this release created after unpacking
the bundle:

  license_terms/
  docs/
  src/
  include/
  test/
  Doxyfile.in
  README.md
  RELEASE_NOTES.txt

Install the product
-------------------

1. If you have not already built the library, or if you want to rebuild the
   library to specify a custom install location, navigate to the unpacked
   product directory and run CMake:

     mkdir <build>
     cd <build>
     cmake [options] -DCMAKE_INSTALL_PREFIX=<install-dir> <path>
     make

   Substitute:

   * '<build>' with a build directory name. The library is built in the
     specified directory.
   * '[options]' with the CMake options to use to build the library.
   * (Optional) '<install-dir>' with an installation directory name. The library
     installs to the specified directory.
   * '<path>' with the path to the root directory of the library source.

   Note: You must have write access for the installation directories:

     * For a default installation, you must have write access for
       '/usr/local/lib/', for the library, and '/usr/local/include/', for the
       header files.
     * For a custom installation, you must have write access for
       '<install-dir>/lib/', for the library, and '<install-dir>/include/', for the
       header files.

2. Install the library, run:

     make install

   An install creates an 'install_manifest.txt' file in the library build
   directory. 'install_manifest.txt' lists the installation locations for the
   library and the header files.

Use Arm RAN Acceleration Library
--------------------------------

To use the Arm RAN Acceleration Library functions, include the armral.h header
file in your C or C++ source code.

For more information, see the README.md file or the documentation on the
Arm developer website:

  https://developer.arm.com/documentation/102249/2101

Tests and benchmarks
--------------------

Tests
~~~~~

Note: To run the included library tests, you must have built the library with
the '-DBUILD_TESTING=On' CMake option.

To run the included tests, use:

  make check

The tests check that the optimized library implementation of a function matches
the results of a reference implementation. Test times vary from system to
system, but typically only take a few seconds.

Benchmarks
~~~~~~~~~~

Note: To run the included benchmark tests, you must have built the library with
the '-DBUILD_TESTING=On' CMake option.

To run the benchmarks, use:

  make bench

Benchmark results are printed as JSON objects. To further process these objects,
you can collect or pipe them into other scripts.

Uninstall
---------

To uninstall the library, navigate to the library build directory that you
previously ran 'make install' in, and run:

  cat install_manifest.txt | xargs rm

Support
=======

Documentation for using this Arm RAN Acceleration Library package is available
on the Arm developer website at:

  https://developer.arm.com/solutions/infrastructure/developer-resources/5g/ran

Reference documentation for the supported routines in Arm RAN Acceleration
Library is available at:

  https://developer.arm.com/documentation/102249/2101

If you have Doxygen installed on your your system, you can build your own HTML
version of the documentation using CMake. To build the HTML documentation, use:

  make docs

If you have any issues with the installation, content, or use of this release,
raise a question on Developer Community Forum at:

  https://community.arm.com/developer/f/infrastructure-solutions

These deliverables are being released under the terms of the agreement between
Arm and each licensee (the “Agreement”). All planned verification and
validation is complete. The release is suitable for volume production under
the terms of the Agreement.

Release history
===============

A full release history (with release notes) for Arm RAN Acceleration Library
is available on the Arm developer website:

  https://developer.arm.com/solutions/infrastructure/developer-resources/5g/ran/release-history