Impact of SpectreAndMeltdown Patches
====================================

Following sections list changes to VPP throughput performance after
applying patches addressing security vulnerabilities referred to as:
Meltdown (Variant3: Rogue Data Cache Load) and Spectre (Variant1: Bounds
Check Bypass; Variant2: Branch Target Injection) security
vulnerabilities. Incremental kernel patches for Ubuntu 16.04 LTS as
documented on
`Ubuntu SpectreAndMeltdown page <https://wiki.ubuntu.com/SecurityTeam/KnowledgeBase/SpectreAndMeltdown>`_.
For Spectre additional Processor microcode and BIOS firmware changes are
applied. 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: ../../_static/vpp/meltdown-spectre-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-spectre-impact-ndr-1t1c-top.csv}
      }

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

.. only:: html

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

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

.. only:: html

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

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

.. only:: html

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