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From:   Eric Dumazet <edumazet@google.com>
Date:   Wed, 19 Apr 2023 14:02:20 +0200
Message-ID: <CANn89iJeiEk_Rcoh0odfjK2ocP23HQfOPDhJJ7p_=Q--A2jHJg@mail.gmail.com>
Subject: Re: [PATCH] net: sched: print jiffies when transmit queue time out
To:     Yajun Deng <yajun.deng@linux.dev>
Cc:     jhs@mojatatu.com, xiyou.wangcong@gmail.com, jiri@resnulli.us,
        davem@davemloft.net, kuba@kernel.org, pabeni@redhat.com,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org
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On Wed, Apr 19, 2023 at 1:56=E2=80=AFPM Yajun Deng <yajun.deng@linux.dev> w=
rote:
>
> Although there is watchdog_timeo to let users know when the transmit queu=
e
> begin stall, but dev_watchdog() is called with an interval. The jiffies
> will always be greater than watchdog_timeo.
>
> To let users know the exact time the stall started, print jiffies when
> the transmit queue time out.
>
> Signed-off-by: Yajun Deng <yajun.deng@linux.dev>
> ---


>                                         atomic_long_inc(&txq->trans_timeo=
ut);
>                                         break;
>                                 }
> @@ -522,8 +522,9 @@ static void dev_watchdog(struct timer_list *t)
>
>                         if (unlikely(some_queue_timedout)) {
>                                 trace_net_dev_xmit_timeout(dev, i);
> -                               WARN_ONCE(1, KERN_INFO "NETDEV WATCHDOG: =
%s (%s): transmit queue %u timed out\n",
> -                                      dev->name, netdev_drivername(dev),=
 i);
> +                               WARN_ONCE(1, KERN_INFO "NETDEV WATCHDOG: =
%s (%s): \
> +                                         transmit queue %u timed out %lu=
 jiffies\n",
> +                                         dev->name, netdev_drivername(de=
v), i, some_queue_timedout);

If we really want this, I suggest we export a time in ms units, using
jiffies_to_msecs()