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Date:   Thu, 19 May 2022 15:54:42 +0200
From:   Andrew Lunn <andrew@lunn.ch>
To:     Paolo Abeni <pabeni@redhat.com>
Cc:     David Laight <David.Laight@aculab.com>,
        'Pavan Chebbi' <pavan.chebbi@broadcom.com>,
        Michael Chan <michael.chan@broadcom.com>,
        "netdev@vger.kernel.org" <netdev@vger.kernel.org>,
        "mchan@broadcom.com" <mchan@broadcom.com>,
        David Miller <davem@davemloft.net>
Subject: Re: tg3 dropping packets at high packet rates
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> If the packet processing is 'bursty', you can have idle time and still
> hit now and the 'rx ring is [almost] full' condition. If pause frames
> are enabled, that will cause the peer to stop sending frames: drop can
> happen in the switch, and the local NIC will not notice (unless there
> are counters avaialble for pause frames sent).

You can control pause with ethtool

       ethtool -a|--show-pause devname

       ethtool -A|--pause devname [autoneg on|off] [rx on|off] [tx on|off]

But it depends on the driver implementing these options. So you might
want to try autoneg on, rx off, tx off, for testing.

ethtool should also show you want has been negotiated for pause, if
the driver has implemented that part of the ethtool API.

    Andrew