netdev - Re: [PATCH net-next 5/8] bnxt: add pause frame stats

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Message-ID: <20200911154343.2a319485@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com>
Date:   Fri, 11 Sep 2020 15:43:43 -0700
From:   Jakub Kicinski <kuba@...nel.org>
To:     Michael Chan <michael.chan@...adcom.com>
Cc:     David Miller <davem@...emloft.net>,
        Netdev <netdev@...r.kernel.org>, mkubecek@...e.cz,
        tariqt@...dia.com, saeedm@...dia.com,
        Alexander Duyck <alexander.duyck@...il.com>,
        Andrew Lunn <andrew@...n.ch>
Subject: Re: [PATCH net-next 5/8] bnxt: add pause frame stats

On Fri, 11 Sep 2020 15:34:24 -0700 Michael Chan wrote:
> On Fri, Sep 11, 2020 at 12:53 PM Jakub Kicinski <kuba@...nel.org> wrote:
> >
> > These stats are already reported in ethtool -S.
> > Hopefully they are equivalent to standard stats?  
> 
> Yes.
> 
> >
> > Signed-off-by: Jakub Kicinski <kuba@...nel.org>
> > ---
> >  .../net/ethernet/broadcom/bnxt/bnxt_ethtool.c | 19 +++++++++++++++++++
> >  1 file changed, 19 insertions(+)
> >
> > diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt_ethtool.c b/drivers/net/ethernet/broadcom/bnxt/bnxt_ethtool.c
> > index d0928334bdc8..b5de242766e3 100644
> > --- a/drivers/net/ethernet/broadcom/bnxt/bnxt_ethtool.c
> > +++ b/drivers/net/ethernet/broadcom/bnxt/bnxt_ethtool.c
> > @@ -1778,6 +1778,24 @@ static void bnxt_get_pauseparam(struct net_device *dev,
> >         epause->tx_pause = !!(link_info->req_flow_ctrl & BNXT_LINK_PAUSE_TX);
> >  }
> >
> > +static void bnxt_get_pause_stats(struct net_device *dev,
> > +                                struct ethtool_pause_stats *epstat)
> > +{
> > +       struct bnxt *bp = netdev_priv(dev);
> > +       struct rx_port_stats *rx_stats;
> > +       struct tx_port_stats *tx_stats;
> > +
> > +       if (BNXT_VF(bp) || !(bp->flags & BNXT_FLAG_PORT_STATS))
> > +               return;
> > +
> > +       rx_stats = (void *)bp->port_stats.sw_stats;
> > +       tx_stats = (void *)((unsigned long)bp->port_stats.sw_stats +
> > +                           BNXT_TX_PORT_STATS_BYTE_OFFSET);
> > +
> > +       epstat->rx_pause_frames = rx_stats->rx_pause_frames;
> > +       epstat->tx_pause_frames = tx_stats->tx_pause_frames;  
> 
> This will work, but the types on the 2 sides don't match.  On the
> right hand side, since you are casting to the hardware struct
> rx_port_stats and tx_port_stats, the types are __le64.
> 
> If rx_stats and tx_stats are *u64 and you use these macros:
> 
> BNXT_GET_RX_PORT_STATS64(rx_stats, rx_pause_frames)
> BNXT_GET_TX_PORT_STATS64(tx_stats, tx_pause_frames)
> 
> the results will be the same with native CPU u64 types.

Thanks! My build bot just poked me about this as well.

I don't see any byte swaps in bnxt_get_ethtool_stats() - 
are they not needed there? I'm slightly confused.