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Date:   Thu, 20 Apr 2023 02:49:12 +0000
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From:   "Yajun Deng" <yajun.deng@linux.dev>
Message-ID: <38876115ff2bd4756eca5d8d8f93a48e@linux.dev>
Subject: Re: [PATCH] net: sched: print jiffies when transmit queue time
 out
To:     "Eric Dumazet" <edumazet@google.com>
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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 <20230419115632.738730-1-yajun.deng@linux.dev>
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April 19, 2023 8:02 PM, "Eric Dumazet" <edumazet@google.com> wrote:=0A=0A=
> On Wed, Apr 19, 2023 at 1:56 PM Yajun Deng <yajun.deng@linux.dev> wrote=
:=0A> =0A>> Although there is watchdog_timeo to let users know when the t=
ransmit queue=0A>> begin stall, but dev_watchdog() is called with an inte=
rval. The jiffies=0A>> will always be greater than watchdog_timeo.=0A>> =
=0A>> To let users know the exact time the stall started, print jiffies w=
hen=0A>> the transmit queue time out.=0A>> =0A>> Signed-off-by: Yajun Den=
g <yajun.deng@linux.dev>=0A>> ---=0A>> =0A>> atomic_long_inc(&txq->trans_=
timeout);=0A>> break;=0A>> }=0A>> @@ -522,8 +522,9 @@ static void dev_wat=
chdog(struct timer_list *t)=0A>> =0A>> if (unlikely(some_queue_timedout))=
 {=0A>> trace_net_dev_xmit_timeout(dev, i);=0A>> - WARN_ONCE(1, KERN_INFO=
 "NETDEV WATCHDOG: %s (%s): transmit queue %u timed out\n",=0A>> - dev->n=
ame, netdev_drivername(dev), i);=0A>> + WARN_ONCE(1, KERN_INFO "NETDEV WA=
TCHDOG: %s (%s): \=0A>> + transmit queue %u timed out %lu jiffies\n",=0A>=
> + dev->name, netdev_drivername(dev), i, some_queue_timedout);=0A> =0A> =
If we really want this, I suggest we export a time in ms units, using=0A>=
 jiffies_to_msecs()=0A=0AOK.