Re: [dpdk-dev] [PATCH] doc: announce ixgbe MTU setting limitation

["Lu, Wenzhuo" <wenzhuo.lu@intel.com>]

Hi John,

> -----Original Message-----
> From: Mcnamara, John
> Sent: Thursday, February 9, 2017 1:11 AM
> To: Lu, Wenzhuo; dev@dpdk.org
> Cc: Lu, Wenzhuo; Yigit, Ferruh
> Subject: RE: [dpdk-dev] [PATCH] doc: announce ixgbe MTU setting limitation
> 
> 
> 
> > -----Original Message-----
> > From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Wenzhuo Lu
> > Sent: Tuesday, February 7, 2017 6:23 AM
> > To: dev@dpdk.org
> > Cc: Lu, Wenzhuo <wenzhuo.lu@intel.com>
> > Subject: [dpdk-dev] [PATCH] doc: announce ixgbe MTU setting limitation
> >
> > Signed-off-by: Wenzhuo Lu <wenzhuo.lu@intel.com>
> > ---
> >  doc/guides/nics/ixgbe.rst | 16 ++++++++++++++--
> >  1 file changed, 14 insertions(+), 2 deletions(-)
> >
> > diff --git a/doc/guides/nics/ixgbe.rst b/doc/guides/nics/ixgbe.rst
> > index
> > 3b6851b..1f7d6b3 100644
> > --- a/doc/guides/nics/ixgbe.rst
> > +++ b/doc/guides/nics/ixgbe.rst
> > @@ -185,8 +185,11 @@ As in the case of l3fwd, set configure
> > port_conf.rxmode.hw_ip_checksum=0 to enab  In addition, for improved
> > performance, use -bsz "(32,32),(64,64),(32,32)" in load_balancer to
> > avoid using the default burst size of 144.
> >
> >
> > +Limitations or Known issues
> > +---------------------------
> > +
> >  Malicious Driver Detection not Supported
> > -----------------------------------------
> > +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> >
> >  The Intel x550 series NICs support a feature called MDD (Malicious
> > Driver Detection) which checks the behavior of the VF driver.
> > @@ -207,7 +210,7 @@ it by default.)
> >
> >
> >  Statistics
> > -----------
> > +~~~~~~~~~~
> >
> >  The statistics of ixgbe hardware must be polled regularly in order
> > for it to  remain consistent. Running a DPDK application without
> > polling the statistics will @@ -230,6 +233,15 @@ be calculated as follows:
> >
> >  In order to ensure valid results, it is recommended to poll every 4
> > minutes.
> >
> > +MTU setting
> > +~~~~~~~~~~~
> > +
> > +Although user can set MTU separately on PF and VF ports, ixgbe only
> > +supports one global MTU per physical port.
> > +So when user sets different MTUs on PF and VF ports in one physical
> > +port, the real MTU for all these PF and VF ports is the biggest one.
> > +This behavior is leveraged from kernel driver.
> > +
> 
> Would be slightly better as:
> 
> Although the user can set the MTU separately on PF and VF ports, the ixgbe
> NIC only supports one global MTU per physical port.
> So when the user sets different MTUs on PF and VF ports in one physical port,
> the real MTU for all these PF and VF ports is the largest value set.
> This behavior is based on the kernel driver behavior.
Thanks for this. I'll use update it in the new version.