Re: [dpdk-dev] [PATCH v3] net/ixgbe: include QPRDC in imissed stat

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

Hi, Cody Harris

  More info, you can get the number of dropped packet per queue by stats->q_errors, 
No need to add this into imissed.

> -----Original Message-----
> From: Zhao1, Wei
> Sent: Thursday, May 28, 2020 11:54 AM
> To: Cody Harris <codh@amazon.com>; dev@dpdk.org
> Subject: RE: [dpdk-dev] [PATCH v3] net/ixgbe: include QPRDC in imissed stat
> 
> HI，Cody Harris
> 
> > -----Original Message-----
> > From: dev <dev-bounces@dpdk.org> On Behalf Of Cody Harris
> > Sent: Tuesday, May 19, 2020 1:08 PM
> > To: dev@dpdk.org
> > Cc: Cody Harris <codh@amazon.com>
> > Subject: [dpdk-dev] [PATCH v3] net/ixgbe: include QPRDC in imissed
> > stat
> >
> > The ixgbe imissed statstic originally only contained dropped packets
> > counted by the RXMPC registers. This change includes additional types
> > of packet drops counted by the QPRDC registers.
> >
> > Intel support confimed that the packet drops counted by the QPRDC
> > registers do not double-count drops counted by RXMPC registers:
> >
> > "RXMPC counts packets that are dropped because there is no room in the
> > internal packet buffer.  QPRDC counts packets that are dropped because
> > they can't be transferred to system memory. These packets have been
> > stored in the internal packet buffer, so there should be no overlap with
> RXMPC."
> >
> > Signed-off-by: Cody Harris <codh@amazon.com>
> > ---
> >  drivers/net/ixgbe/ixgbe_ethdev.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/net/ixgbe/ixgbe_ethdev.c
> > b/drivers/net/ixgbe/ixgbe_ethdev.c
> > index a4e5c539d..7284ca28e 100644
> > --- a/drivers/net/ixgbe/ixgbe_ethdev.c
> > +++ b/drivers/net/ixgbe/ixgbe_ethdev.c
> > @@ -3366,7 +3366,7 @@ ixgbe_dev_stats_get(struct rte_eth_dev *dev,
> > struct rte_eth_stats *stats)
> >  	}
> >
> >  	/* Rx Errors */
> > -	stats->imissed  = total_missed_rx;
> > +	stats->imissed  = total_missed_rx + total_qprdc;
> 
> If Rx queue is disabled in the RXDCTL register, packet direct to this queue is
> also dropped and count by this Register QPRDC, but the definition of imissed is
> "Total of RX packets dropped by the HW because there are no available buffer"
> in rte layer.
> So, it maybe mislead users if we mix the 2 statistic, is that so?
> Also, x550 has other definition for this register, we can not mix them.
> 
> 
> >  	stats->ierrors  = hw_stats->crcerrs +
> >  			  hw_stats->mspdc +
> >  			  hw_stats->rlec +
> > --
> > 2.24.1.AMZN