[dpdk-dev] [PATCH] ethdev: don't count missed packets in erroneous packets counter

[Tahhan, Maryam]

> From: Thomas Monjalon [mailto:thomas.monjalon at 6wind.com]
> Sent: Thursday, March 17, 2016 4:41 PM
> To: Igor Ryzhov <iryzhov at nfware.com>
> Cc: dev at dpdk.org; Tahhan, Maryam <maryam.tahhan at intel.com>;
> olivier.matz at 6wind.com
> Subject: Re: [dpdk-dev] [PATCH] ethdev: don't count missed packets in
> erroneous packets counter
> 
> CC Maryam and Olivier who had discussions about imissed and other
> stats:
> 	http://dpdk.org/ml/archives/dev/2015-August/022905.html
> 	http://dpdk.org/ml/archives/dev/2015-September/023351.html
> 	http://dpdk.org/ml/archives/dev/2015-September/023612.html
> 
> 2016-03-10 16:03, Igor Ryzhov:
> > Comment for "ierrors" counter says that it counts erroneous received
> packets. But for some reason "imissed" counter is added to "ierrors"
> counter in most drivers. It is a mistake, because missed packets are
> obviously not received. This patch fixes it.
> 
> According to this patch
> 	http://dpdk.org/browse/dpdk/commit/?id=70bdb186
> imissed was kept in ierrors because of backward compatibility.
> I'm OK to remove imissed from ierrors.
> 
> Fixes: 70bdb18657da ("ethdev: add Rx error counters for missed, badcrc
> and badlen packets")
> Fixes: 6bfe648406b5 ("i40e: add Rx error statistics")
> Fixes: 856505d303f4 ("cxgbe: add port statistics")
> 
> Acked-by: Thomas Monjalon <thomas.monjalon at 6wind.com>

Looks fine, but make sure to add an explicit comment in release notes somewhere to flag the change. In case any apps were accounting for imissed as part of ierrors like testpmd was: 

-		if (((stats->ierrors - stats->imissed) + stats->rx_nombuf) > 0) {
+		if ((stats->ierrors + stats->rx_nombuf) > 0) {
 			printf("  RX-error:%"PRIu64"\n", stats->ierrors);
 			printf("  RX-nombufs:             %14"PRIu64"\n",
 			       stats->rx_nombuf);