[dpdk-dev] [PATCH v2 1/3] doc: updated i40e enabling additonal fnct in gsg

Thomas Monjalon thomas.monjalon at 6wind.com
Fri Dec 19 22:42:26 CET 2014


> --- a/doc/guides/linux_gsg/enable_func.rst
> +++ b/doc/guides/linux_gsg/enable_func.rst
> @@ -171,6 +171,10 @@ Please note that while using iommu=pt is compulsory for igb_uio driver, the vfio
>  High Performance of Small Packets on 40G NIC
>  --------------------------------------------
>  
> +As there might be firmware fixes for performance enhancement in latest version
> +of firmware image, the firmware update might be needed for getting high performance.
> +Check with the local Intel's Network Division application engineers for firmware updates.
> +
>  Enabling Extended Tag and Setting Max Read Request Size
>  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>  
> @@ -198,3 +202,13 @@ Use 16 Bytes RX Descriptor Size
>  
>  As i40e PMD supports both 16 and 32 bytes RX descriptor sizes, and 16 bytes size can provide helps to high performance of small packets.
>  Configuration of CONFIG_RTE_LIBRTE_I40E_16BYTE_RX_DESC in config files can be changed to use 16 bytes size RX descriptors.
> +
> +High Performance and per Packet Latency Tradeoff
> +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> +
> +Due to the hardware design, the interrupt signal inside NIC is needed for per
> +packet descriptor write-back. The minimum interval of interrupts could be set
> +at compile time by CONFIG_RTE_LIBRTE_I40E_ITR_INTERVAL in configuration files.
> +Though there is a default configuration, the interval could be tuned by the
> +users with that configuration item depends on what the user cares about more,
> +performance or per packet latency.

This kind of hardware information is not specific to Linux.
I think we should open some guides dedicated to drivers design.
Examples:
	- doc/guides/drivers/i40e/
	- doc/guides/drivers/enic/
	- etc
Any volunteer to start this new doc directory?

-- 
Thomas


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