From mboxrd@z Thu Jan 1 00:00:00 1970 From: Florian Fainelli Subject: Re: [PATCH net-next v2] net: bcmgenet: collect Rx discarded packet count Date: Tue, 10 Mar 2015 17:08:02 -0700 Message-ID: References: <20150310225500.8FA34220365@puck.mtv.corp.google.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Cc: netdev , David Miller , Jaedon Shin To: Petri Gynther Return-path: Received: from mail-ig0-f171.google.com ([209.85.213.171]:37416 "EHLO mail-ig0-f171.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751878AbbCKAIn (ORCPT ); Tue, 10 Mar 2015 20:08:43 -0400 Received: by igbhn18 with SMTP id hn18so36351111igb.2 for ; Tue, 10 Mar 2015 17:08:42 -0700 (PDT) In-Reply-To: <20150310225500.8FA34220365@puck.mtv.corp.google.com> Sender: netdev-owner@vger.kernel.org List-ID: 2015-03-10 15:55 GMT-07:00 Petri Gynther : > Bits 31:16 of RDMA_PROD_INDEX contain Rx discarded packet count, which > are the Rx packets that had to be dropped by MAC hardware since there > was no room on the Rx queue. Add code to collect this information into > the netdev stats. > > Signed-off-by: Petri Gynther > --- > drivers/net/ethernet/broadcom/genet/bcmgenet.c | 18 ++++++++++++++++++ > drivers/net/ethernet/broadcom/genet/bcmgenet.h | 1 + > 2 files changed, 19 insertions(+) > > diff --git a/drivers/net/ethernet/broadcom/genet/bcmgenet.c b/drivers/net/ethernet/broadcom/genet/bcmgenet.c > index 275be56..d3be1aeb 100644 > --- a/drivers/net/ethernet/broadcom/genet/bcmgenet.c > +++ b/drivers/net/ethernet/broadcom/genet/bcmgenet.c > @@ -1384,9 +1384,27 @@ static unsigned int bcmgenet_desc_rx(struct bcmgenet_priv *priv, > int len, err; > unsigned int rxpktprocessed = 0, rxpkttoprocess; > unsigned int p_index; > + unsigned int discards; > unsigned int chksum_ok = 0; > > p_index = bcmgenet_rdma_ring_readl(priv, index, RDMA_PROD_INDEX); > + > + discards = (p_index >> DMA_P_INDEX_DISCARD_CNT_SHIFT) & > + DMA_P_INDEX_DISCARD_CNT_MASK; > + if (discards > ring->old_discards) { > + discards = discards - ring->old_discards; > + dev->stats.rx_missed_errors += discards; > + dev->stats.rx_errors += discards; > + ring->old_discards += discards; > + > + /* Clear HW register when we reach 75% of maximum 0xFFFF */ > + if (ring->old_discards >= 0xC000) { > + ring->old_discards = 0; > + bcmgenet_rdma_ring_writel(priv, index, 0, > + RDMA_PROD_INDEX); > + } > + } So this looks better, I am wondering if we should not actually do this in the case where we run out of memory, because this is pretty much when the discard counter is likely to be increased? > + > p_index &= DMA_P_INDEX_MASK; > > if (likely(p_index >= ring->c_index)) > diff --git a/drivers/net/ethernet/broadcom/genet/bcmgenet.h b/drivers/net/ethernet/broadcom/genet/bcmgenet.h > index 17443db..2a81138 100644 > --- a/drivers/net/ethernet/broadcom/genet/bcmgenet.h > +++ b/drivers/net/ethernet/broadcom/genet/bcmgenet.h > @@ -548,6 +548,7 @@ struct bcmgenet_rx_ring { > unsigned int read_ptr; /* Rx ring read pointer */ > unsigned int cb_ptr; /* Rx ring initial CB ptr */ > unsigned int end_ptr; /* Rx ring end CB ptr */ > + unsigned int old_discards; > }; > > /* device context */ > -- > 2.2.0.rc0.207.ga3a616c > -- Florian