[dpdk-dev] i40e: Steps and required configurations of how to achieve the best performance!

David Marchand david.marchand at 6wind.com
Wed Sep 17 10:33:46 CEST 2014


Hello,

Some questions/comments :

On Wed, Sep 17, 2014 at 6:18 AM, Zhang, Helin <helin.zhang at intel.com> wrote:

> -- *Extended Tag: Enabled
> Note that 'Extended Tag' might not be seen in some BIOS, see 'compile
> settings' for doing that at runtime.
>

I am not sure I understand this point.

Either you have a bios that configures extended tag and you don't need
anything in the dpdk or your bios does not support it and you must set it
at runtime ?
Then why not just set it at runtime and we avoid touching bios config ?


5. Compile Settings:
> -- Change below configuration items in config files
>   CONFIG_RTE_PCI_CONFIG=y
>   CONFIG_RTE_PCI_EXTENDED_TAG="on"
>

Why have this build option for what looks to be a runtime decision ?
Why don't we have RTE_PCI_CONFIG always set and extended tag to "on" ?
(which means that we can get rid of these build options)

Looking at igb_uio code, I am a bit concerned that this option affects all
"igb_uio" pci devices in dpdk.
Can you ensure me that any pci device going through igb_uio (em, igb, ixgbe
etc... devices) will behave well with this option enabled ?

It would be better to have a per-device (or per-pmd) option.

Plus, build option should really be avoided for any feature in dpdk (and we
have a lot of cleanup work about this ...).



>   CONFIG_RTE_LIBRTE_I40E_16BYTE_RX_DESC=y
>

 Why is it disabled as a default ?

Thanks.

-- 
David Marchand


More information about the dev mailing list