Impact of Meltdown Patches
==========================

Following sections list changes to VPP throughput performance after applying
patches addressing security vulnerabilities referred to as Meltdown
(Variant3: Rogue Data Cache Load). Incremental kernel patches are
applied for Ubuntu 16.04LTS as documented on
`Ubuntu SpectreAndMeltdown page <https://wiki.ubuntu.com/SecurityTeam/KnowledgeBase/SpectreAndMeltdown>`_.
Detailed listing of used software versions and patches is documented in
:ref:`test_environment`.

NDR and PDR packet throughput results are compared for 1-core/1-thread,
2-cores/2-threads and 4-cores/4-threads VPP configurations, with
reference performance numbers coming from tests without the Meltdown
patches. Tables show test results grouped into Best 20 changes (minimal
performance impact), followed by Worst 20 changes (maximal performance
impact). All results are also provided in downloadable CSV and pretty
ASCII formats.

NDR throughput: Best 20 changes
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

.. only:: html

   .. csv-table::
      :align: center
      :file: ../../../_build/_static/vpp/meltdown-impact-ndr-1t1c-top.csv

.. only:: latex

   .. raw:: latex

      \makeatletter
      \csvset{
        perfimprovements column width/.style={after head=\csv@pretable\begin{longtable}{m{4cm} m{#1} m{#1} m{#1} m{#1} m{#1}}\csv@tablehead},
      }
      \makeatother

      {\tiny
      \csvautobooklongtable[separator=comma,
        respect all,
        no check column count,
        perfimprovements column width=1cm,
        late after line={\\\hline},
        late after last line={\end{longtable}}
        ]{../_build/_static/vpp/meltdown-impact-ndr-1t1c-top.csv}
      }

NDR throughput: Worst 20 changes
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

.. only:: html

   .. csv-table::
      :align: center
      :file: ../../../_build/_static/vpp/meltdown-impact-ndr-1t1c-bottom.csv

.. only:: latex

   .. raw:: latex

      \makeatletter
      \csvset{
        perfimprovements column width/.style={after head=\csv@pretable\begin{longtable}{m{4cm} m{#1} m{#1} m{#1} m{#1} m{#1}}\csv@tablehead},
      }
      \makeatother

      {\tiny
      \csvautobooklongtable[separator=comma,
        respect all,
        no check column count,
        perfimprovements column width=1cm,
        late after line={\\\hline},
        late after last line={\end{longtable}}
        ]{../_build/_static/vpp/meltdown-impact-ndr-1t1c-bottom.csv}
      }

.. only:: html

NDR throughput: All changes
~~~~~~~~~~~~~~~~~~~~~~~~~~~

Complete results for all NDR tests are available in a CSV and pretty
ASCII formats:

  - `csv format for 1t1c <../../_static/vpp/meltdown-impact-ndr-1t1c-full.csv>`_,
  - `csv format for 2t2c <../../_static/vpp/meltdown-impact-ndr-2t2c-full.csv>`_,
  - `csv format for 4t4c <../../_static/vpp/meltdown-impact-ndr-4t4c-full.csv>`_,
  - `pretty ASCII format for 1t1c <../../_static/vpp/meltdown-impact-ndr-1t1c-full.txt>`_,
  - `pretty ASCII format for 2t2c <../../_static/vpp/meltdown-impact-ndr-2t2c-full.txt>`_,
  - `pretty ASCII format for 4t4c <../../_static/vpp/meltdown-impact-ndr-4t4c-full.txt>`_.

PDR throughput: Best 20 changes
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

.. only:: html

   .. csv-table::
      :align: center
      :file: ../../../_build/_static/vpp/meltdown-impact-pdr-1t1c-top.csv

.. only:: latex

   .. raw:: latex

      \makeatletter
      \csvset{
        perfimprovements column width/.style={after head=\csv@pretable\begin{longtable}{m{4cm} m{#1} m{#1} m{#1} m{#1} m{#1}}\csv@tablehead},
      }
      \makeatother

      {\tiny
      \csvautobooklongtable[separator=comma,
        respect all,
        no check column count,
        perfimprovements column width=1cm,
        late after line={\\\hline},
        late after last line={\end{longtable}}
        ]{../_build/_static/vpp/meltdown-impact-pdr-1t1c-top.csv}
      }

PDR throughput: Worst 20 changes
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

.. only:: html

   .. csv-table::
      :align: center
      :file: ../../../_build/_static/vpp/meltdown-impact-pdr-1t1c-bottom.csv

.. only:: latex

   .. raw:: latex

      \makeatletter
      \csvset{
        perfimprovements column width/.style={after head=\csv@pretable\begin{longtable}{m{4cm} m{#1} m{#1} m{#1} m{#1} m{#1}}\csv@tablehead},
      }
      \makeatother

      {\tiny
      \csvautobooklongtable[separator=comma,
        respect all,
        no check column count,
        perfimprovements column width=1cm,
        late after line={\\\hline},
        late after last line={\end{longtable}}
        ]{../_build/_static/vpp/meltdown-impact-pdr-1t1c-bottom.csv}
      }

.. only:: html

PDR throughput: All changes
~~~~~~~~~~~~~~~~~~~~~~~~~~~

Complete results for all PDR tests are available in a CSV and pretty
ASCII formats:

  - `csv format for 1t1c <../../_static/vpp/meltdown-impact-pdr-1t1c-full.csv>`_,
  - `csv format for 2t2c <../../_static/vpp/meltdown-impact-pdr-2t2c-full.csv>`_,
  - `csv format for 4t4c <../../_static/vpp/meltdown-impact-pdr-4t4c-full.csv>`_,
  - `pretty ASCII format for 1t1c <../../_static/vpp/meltdown-impact-pdr-1t1c-full.txt>`_,
  - `pretty ASCII format for 2t2c <../../_static/vpp/meltdown-impact-pdr-2t2c-full.txt>`_,
  - `pretty ASCII format for 4t4c <../../_static/vpp/meltdown-impact-pdr-4t4c-full.txt>`_.