Re: [dpdk-dev] [PATCH v2 1/3] i40e: enable extended tag

["Zhang, Helin" <helin.zhang@intel.com>]

> -----Original Message-----
> From: Richardson, Bruce
> Sent: Tuesday, February 23, 2016 6:45 PM
> To: Zhang, Helin <helin.zhang@intel.com>
> Cc: dev@dpdk.org; zhe.tag@intel.com
> Subject: Re: [dpdk-dev] [PATCH v2 1/3] i40e: enable extended tag
> 
> On Mon, Feb 22, 2016 at 11:59:43AM +0800, Helin Zhang wrote:
> > PCIe feature of 'Extended Tag' is important for 40G performance.
> > It adds its enabling during each port initialization, to ensure the
> > high performance.
> >
> > Signed-off-by: Helin Zhang <helin.zhang@intel.com>
> > ---
> >  doc/guides/rel_notes/release_16_04.rst |  6 ++++
> >  drivers/net/i40e/i40e_ethdev.c         | 65
> ++++++++++++++++++++++++++++++++--
> >  2 files changed, 68 insertions(+), 3 deletions(-)
> >
> > v2:
> >  - Changed the type of return value of i40e_enable_extended_tag() to 'void'.
> >
> > diff --git a/doc/guides/rel_notes/release_16_04.rst
> > b/doc/guides/rel_notes/release_16_04.rst
> > index 5786f74..bed5779 100644
> > --- a/doc/guides/rel_notes/release_16_04.rst
> > +++ b/doc/guides/rel_notes/release_16_04.rst
> > @@ -46,6 +46,12 @@ This section should contain new features added in this
> release. Sample format:
> >
> >  * **Added vhost-user live migration support.**
> >
> > +* **i40e: Enabled extended tag.**
> > +
> > +  It enabled extended tag by checking and writing corresponding PCI
> > + config  space bytes, to boost the performance. In the meanwhile, it
> > + deprecated the  legacy way via reading/writing sysfile supported by kernel
> module of igb_uio.
> > +
> 
> Hi Helin,
> 
> does this really need to go into the release notes? Is it a user-visible change that
> affects the user experience in any way?
Previously we enable it in eal via igb_uio sys file (by default, it is disabled), which was deprecated now, and will be removed from next release.
All now added into i40e PMD init only.
Yes, user might see the performance boost without doing anything, which is different from previous version of DPDK.

I think it should be mentioned somewhere. Any better idea?
Thanks,
Helin

> 
> /Bruce