Re: [PATCH v2 1/2] net/i40e: fix clear xstats bug in vf port

["Zhao1, Wei" <wei.zhao1@intel.com>]

Hi, jingjing

> -----Original Message-----
> From: Wu, Jingjing
> Sent: Saturday, September 9, 2017 11:16 AM
> To: Zhao1, Wei <wei.zhao1@intel.com>; Yigit, Ferruh
> <ferruh.yigit@intel.com>; dev@dpdk.org
> Subject: RE: [dpdk-dev] [PATCH v2 1/2] net/i40e: fix clear xstats bug in vf port
> 
> 
> 
> > -----Original Message-----
> > From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Zhao1, Wei
> > Sent: Friday, September 1, 2017 10:30 AM
> > To: Yigit, Ferruh <ferruh.yigit@intel.com>; dev@dpdk.org
> > Subject: Re: [dpdk-dev] [PATCH v2 1/2] net/i40e: fix clear xstats bug
> > in vf port
> >
> > Hi,  Ferruh
> >
> > > -----Original Message-----
> > > From: Yigit, Ferruh
> > > Sent: Friday, September 1, 2017 12:54 AM
> > > To: Zhao1, Wei <wei.zhao1@intel.com>; dev@dpdk.org
> > > Subject: Re: [dpdk-dev] [PATCH v2 1/2] net/i40e: fix clear xstats
> > > bug in vf port
> > >
> > > On 8/29/2017 3:28 AM, Wei Zhao wrote:
> > > > There is a bug in vf clear xstats command, it do not record the
> > > > statics data in offset struct member.So, vf need to keep record of
> > > > xstats data from pf and update the statics according to offset.
> > > >
> > > > Fixes: da61cd0849766 ("i40evf: add extended stats")
> > > >
> > > > Signed-off-by: Wei Zhao <wei.zhao1@intel.com>
> > > >
> > > > ---
> > > >
> > > > Changes in v2:
> > > >
> > > >  fix patch log check warning.
> > > > ---
> > > >  app/test-pmd/config.c             |  6 ++--
> > > >  drivers/net/i40e/i40e_ethdev_vf.c | 64
> > > > ++++++++++++++++++++++++++++++++++++++-
> > > >  2 files changed, 67 insertions(+), 3 deletions(-)
> > > >
> > > > diff --git a/app/test-pmd/config.c b/app/test-pmd/config.c index
> > > > 3ae3e1c..14131d6 100644
> > > > --- a/app/test-pmd/config.c
> > > > +++ b/app/test-pmd/config.c
> > > > @@ -203,8 +203,10 @@ nic_stats_display(portid_t port_id)
> > > >  	if (diff_cycles > 0)
> > > >  		diff_cycles = prev_cycles[port_id] - diff_cycles;
> > > >
> > > > -	diff_pkts_rx = stats.ipackets - prev_pkts_rx[port_id];
> > > > -	diff_pkts_tx = stats.opackets - prev_pkts_tx[port_id];
> > > > +	diff_pkts_rx = (stats.ipackets > prev_pkts_rx[port_id]) ?
> > > > +		(stats.ipackets - prev_pkts_rx[port_id]) : 0;
> > > > +	diff_pkts_tx = (stats.opackets > prev_pkts_tx[port_id]) ?
> > > > +		(stats.opackets - prev_pkts_tx[port_id]) : 0;
> > >
> > > I guess this testpmd update is not directly related to this patch,
> > > but to protect testpmd against value overflow? Can this be another patch?
> >
> > Nonono, this code change is directly related to this patch, if we do
> > not do this code change, the diff_pkts_rx and diff_pkts_tx statistic
> > data will be wrong  when the first time after clear xstats command.
> >
> Yes, the fix will make the error happen, but this is the fix of the clear xstats
> issue.
> You can create a separate patch for it just to make clearer.

OK, I will create a separate patch for it later.

> 
> <......>
> > This bug only appear after use CLI "clear port xstats 0". So it is not
> > easy to detect this bug.
> > After using this fix patch ,the big user who report this issue has
> > feed back it work well now.
> > The root cause is not so complicated, when the pf which admin this vf
> > is in kernel state, DPDK can not Give pf the info to clear and update
> > offset command, so vf can only keep record the offset data in DPDK VF
> > port locally.
> >
> That was because i40evf PMD doesn't support the ops "stats_reset", but
> "xstats_reset"
> Is implemented when xstats are introduced in i40vf PMD.
> I think you also need to add the ops "stats_reset", testing can cover this basic
> case then.


Yes , I have create a new patch for add support of reset stats in vf port.
http://dpdk.org/dev/patchwork/patch/28046/
> 
> Thanks
> Jingjing