Hi, Wujingjing and Kyle Larose
> -----Original Message----- > From: Zhao1, Wei > Sent: Tuesday, August 2, 2016 11:27 AM > To: Wu, Jingjing <jingjing.wu at intel.com>; Lu, Wenzhuo > <wenzhuo.lu at intel.com> > Cc: dev at dpdk.org > Subject: RE: [dpdk-dev] [PATCH v2] net/i40e: fix Rx statistic inconsistent > > Hi,Wu jingjing and wenzhuo > > > -----Original Message----- > > From: Zhao1, Wei > > Sent: Monday, August 1, 2016 4:58 PM > > To: 'Kyle Larose' <eomereadig at gmail.com> > > Cc: dev at dpdk.org > > Subject: RE: [dpdk-dev] [PATCH v2] net/i40e: fix Rx statistic > > inconsistent > > > > Hi, Kyle Larose > > The core problem is i40e has no statistic of discard bytes, that > > means even if when ports are not stopped, the statistic rx_good_bytes > > is consist of discard > > bytes?is that reasonable? In other words, I can just minus discard > > bytes from rx_good_bytes if I can get discard bytes number, that is much > better. > > > > -----Original Message----- > > From: Kyle Larose [mailto:eomereadig at gmail.com] > > Sent: Saturday, July 30, 2016 1:17 AM > > To: Zhao1, Wei <wei.zhao1 at intel.com> > > Cc: dev at dpdk.org > > Subject: Re: [dpdk-dev] [PATCH v2] net/i40e: fix Rx statistic > > inconsistent > > > > On Fri, Jul 29, 2016 at 4:50 AM, Wei Zhao1 <wei.zhao1 at intel.com> wrote: > > > rx_good_bytes and rx_good_packets statistic is inconsistent when > > > port stopped,ipackets statistic is minus the discard packets but > > > rx_bytes statistic not.Also,i40e has no statistic of discard bytes, > > > so we have to delete discard packets item from rx_good_packets statistic. > > > > > > Fixes: 9aace75fc82e ("i40e: fix statistics") > > > > > > Signed-off-by: Wei Zhao1 <wei.zhao1 at intel.com> > > > --- > > > drivers/net/i40e/i40e_ethdev.c | 3 +-- > > > 1 file changed, 1 insertion(+), 2 deletions(-) > > > > > > diff --git a/drivers/net/i40e/i40e_ethdev.c > > > b/drivers/net/i40e/i40e_ethdev.c index 11a5804..553dfd9 100644 > > > --- a/drivers/net/i40e/i40e_ethdev.c > > > +++ b/drivers/net/i40e/i40e_ethdev.c > > > @@ -2319,8 +2319,7 @@ i40e_dev_stats_get(struct rte_eth_dev *dev, > > > struct rte_eth_stats *stats) > > > > > > stats->ipackets = pf->main_vsi->eth_stats.rx_unicast + > > > pf->main_vsi->eth_stats.rx_multicast + > > > - pf->main_vsi->eth_stats.rx_broadcast - > > > - pf->main_vsi->eth_stats.rx_discards; > > > + pf->main_vsi->eth_stats.rx_broadcast; > > > stats->opackets = pf->main_vsi->eth_stats.tx_unicast + > > > pf->main_vsi->eth_stats.tx_multicast + > > > pf->main_vsi->eth_stats.tx_broadcast; > > > -- > > > 2.5.5 > > > > > > > Is it not worse to report a received packet when no packet was > > actually received by the upper layers under normal operations than to > > ensure that packets and bytes are consistent when an interface is > > stopped? It seems like the first case is much more likely to occur than the > second. > > > > Are we just introducing a new issue to fix another? > > > > How does this behaviour compare to other NICs? Does the ixgbe report > > discarded packets in its ipackets? My reading of the driver is that it does > > not. > > In fact, it does something interesting to deal with the > > problem: > > > > from: > > http://dpdk.org/browse/dpdk/tree/drivers/net/ixgbe/ixgbe_ethdev.c > > > > /* > > * An errata states that gprc actually counts good + missed packets: > > * Workaround to set gprc to summated queue packet receives */ > > hw_stats- > > >gprc = *total_qprc; > > > > total_gprc is equal to the sum of the qprc per queue. Can we do > > something similar on the i40e instead of adding unicast, mulitcast and > broadcast? > > > I have checked ixgbe code about Rx statistic, in function > ixgbe_read_stats_registers() we can find the rx_good_bytes and > rx_good_packets statistic. > It is listed below, we can see rx_good_packets is also just addition of Queue > Packets Received Count and not minused discard packet number. > Is there some wrong of understanding? > > for (i = 0; i < IXGBE_QUEUE_STAT_COUNTERS; i++) { > ...... > *total_qprc += hw_stats->qprc[i]; > *total_qbrc += hw_stats->qbrc[i]; > ...... > } The problem is i40e has no statistic of discard bytes, so it is impossible to minus discard bytes from rx_good_bytes . If you think it's not reasonable to Delete rx_discards iterm from rx_good_packets statistic, this patch will be superseded. Because I didn't find other way to correct this problem at present.
