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

Wu, Jingjing jingjing.wu at intel.com
Sat Sep 9 05:15:43 CEST 2017



> -----Original Message-----
> From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of Zhao1, Wei
> Sent: Friday, September 1, 2017 10:30 AM
> To: Yigit, Ferruh <ferruh.yigit at intel.com>; dev at 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 at intel.com>; dev at 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 at 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.

<......>
> 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.

Thanks
Jingjing


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