Re: [dpdk-dev] [PATCH] doc: introduce PVP reference benchmark

[Maxime Coquelin <maxime.coquelin@redhat.com>]

Hi John,

On 11/24/2016 06:38 PM, Mcnamara, John wrote:
>> -----Original Message-----
>> From: Maxime Coquelin [mailto:maxime.coquelin@redhat.com]
>> Sent: Wednesday, November 23, 2016 9:00 PM
>> To: yuanhan.liu@linux.intel.com; thomas.monjalon@6wind.com; Mcnamara, John
>> <john.mcnamara@intel.com>; Yang, Zhiyong <zhiyong.yang@intel.com>;
>> dev@dpdk.org
>> Cc: fbaudin@redhat.com; Maxime Coquelin <maxime.coquelin@redhat.com>
>> Subject: [PATCH] doc: introduce PVP reference benchmark
>>
>> Having reference benchmarks is important in order to obtain reproducible
>> performance figures.
>>
>> This patch describes required steps to configure a PVP setup using testpmd
>> in both host and guest.
>>
>> Not relying on external vSwitch ease integration in a CI loop by not being
>> impacted by DPDK API changes.
>
> Hi Maxime,
>
> Thanks for the detailed doc and this initiative. Some minor documentation
> comments below.
>
>
>
>> +
>> +Setup overview
>> +..............
>
> This level header should be ---------, even if it looks like dots in the
> contribution guide:
>
>     http://dpdk.org/doc/guides/contributing/documentation.html#section-headers
>
>
>> +
>> +.. figure:: img/pvp_2nics.svg
>> +
>> +  PVP setup using 2 NICs
>> +
>
> The figure needs a target so it can be used with :numref:, like this:
>
> .. _figure_pvp_2nics:
>
> .. figure:: img/pvp_2nics.*
>
>    PVP setup using 2 NICs
>
>
>> +DPDK build
>> +~~~~~~~~~~
>> +
>
> Put a one line description at the start of each section, even if it is just: Build DPDK:
Ok.
>
>
>
>> +Testpmd launch
>> +~~~~~~~~~~~~~~
>> +
>> +#. Assign NICs to DPDK:
>> +
>> +   .. code-block:: console
>> +
>> +    modprobe vfio-pci
>> +    $RTE_SDK/install/sbin/dpdk-devbind -b vfio-pci 0000:11:00.0
>> + 0000:11:00.1
>> +
>> +*Note: Sandy Bridge family seems to have some limitations wrt its
>> +IOMMU, giving poor performance results. To achieve good performance on
>> +these machines, consider using UIO instead.*
>
> This would be better as an RST note:
>
> #. Assign NICs to DPDK:
>
>    .. code-block:: console
>
>       modprobe vfio-pci
>       $RTE_SDK/install/sbin/dpdk-devbind -b vfio-pci 0000:11:00.0 0000:11:00.1
>
>    .. Note::
>
>       The Sandy Bridge family seems to have some IOMMU limitations giving poor
>       performance results. To achieve good performance on these machines
>       consider using UIO instead.
This is indeed better, thanks for the tip!

About this note, I couldn't find official information about this
problem.

Do you confirm the issue, or I misconfigured something?

I'll also add something about security implications of using UIO.
>
>
>
>> +First, SELinux policy needs to be set to permissiven, as testpmd is run
>> +as root (reboot required):
>
> s/permissiven/permissive/
>
>
> There are a couple of trailing whitespace errors as well at build as well.

Ok, I will rework all this.

Thanks for the review,
Maxime