.. IMPORTANT: this file is auto-generated from borg's built-in help, do not edit!

.. _borg_benchmark_cpu:

borg benchmark cpu
------------------
.. code-block:: none

    borg [common options] benchmark cpu [options]

.. only:: html

    .. class:: borg-options-table

    +-------------------------------------------------------+-------------------+--------------------------------+
    | **options**                                                                                                |
    +-------------------------------------------------------+-------------------+--------------------------------+
    |                                                       | ``--json``        | format output as JSON          |
    +-------------------------------------------------------+-------------------+--------------------------------+
    |                                                       | ``--chunking``    | benchmark the chunkers         |
    +-------------------------------------------------------+-------------------+--------------------------------+
    |                                                       | ``--hashing``     | benchmark the hashes / MACs    |
    +-------------------------------------------------------+-------------------+--------------------------------+
    |                                                       | ``--encrypting``  | benchmark the encryption modes |
    +-------------------------------------------------------+-------------------+--------------------------------+
    |                                                       | ``--compressing`` | benchmark the compressors      |
    +-------------------------------------------------------+-------------------+--------------------------------+
    |                                                       | ``--msgpacking``  | benchmark msgpack item packing |
    +-------------------------------------------------------+-------------------+--------------------------------+
    | .. class:: borg-common-opt-ref                                                                             |
    |                                                                                                            |
    | :ref:`common_options`                                                                                      |
    +-------------------------------------------------------+-------------------+--------------------------------+

    .. raw:: html

        <script type='text/javascript'>
        $(document).ready(function () {
            $('.borg-options-table colgroup').remove();
        })
        </script>

.. only:: latex



    options
        --json           format output as JSON
        --chunking       benchmark the chunkers
        --hashing        benchmark the hashes / MACs
        --encrypting     benchmark the encryption modes
        --compressing    benchmark the compressors
        --msgpacking     benchmark msgpack item packing


    :ref:`common_options`
        |

Description
~~~~~~~~~~~

This command benchmarks miscellaneous CPU-bound Borg operations.

It creates input data in memory, runs the operation and then displays throughput.
To reduce outside influence on the timings, please make sure to run this with:

- an otherwise as idle as possible machine
- enough free memory so there will be no slow down due to paging activity

By default all benchmarks run. Give one or more of --chunking, --hashing,
--encrypting, --compressing, --msgpacking to run only those.

Some algorithms use multiple threads only above a size threshold, so the
hashes and the compressors are measured at more than one buffer size: the
hashes at 64MiB (roughly pack-sized) and 2MiB (a typical borg chunk), both above
blake3's threshold, the compressors at 2MiB and 128kiB, which is below
zstd's. Within a section every row processes the same total number of
bytes - 1 GiB, or 10 MiB for the compressors - so the throughput column is
comparable between rows.

The compressors work on synthetic text-like data that compresses about 4x
at zstd,3. Random data would be the worst possible input: no codec can
compress it, so all of them would take their incompressible fast path and
the levels would barely differ.