From: Jakub Kicinski <kuba@kernel.org>
To: Jay Vosburgh <jay.vosburgh@canonical.com>
Cc: "David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Paolo Abeni <pabeni@redhat.com>,
netdev@vger.kernel.org, Jonathan Toppins <jtoppins@redhat.com>,
Veaceslav Falico <vfalico@gmail.com>,
Andy Gospodarek <andy@greyhouse.net>
Subject: Re: [PATCH net] veth: Add updating of trans_start
Date: Tue, 21 Jun 2022 12:52:39 -0700 [thread overview]
Message-ID: <20220621125233.1d36737b@kicinski-fedora-PC1C0HJN> (raw)
In-Reply-To: <20220617175550.6a3602ab@kernel.org>
On Fri, 17 Jun 2022 17:55:50 -0700 Jakub Kicinski wrote:
> > >I presume it needs it to check if the device has transmitted anything
> > >in the last unit of time, can we look at the device stats for LLTX for
> > >example?
> >
> > Yes, that's the use case.
> >
> > Hmm. Polling the device stats would likely work for software
> > devices, although the unit of time varies (some checks are fixed at one
> > unit, but others can be N units depending on the missed_max option
> > setting).
> >
> > Polling hardware devices might not work; as I recall, some
> > devices only update the statistics on timespans on the order of seconds,
> > e.g., bnx2 and tg3 appear to update once per second. But those do
> > update trans_start.
>
> Right, unfortunately.
>
> > The question then becomes how to distinguish a software LLTX
> > device from a hardware LLTX device.
>
> If my way of thinking about trans_start is correct then we can test
> for presence of ndo_tx_timeout. Anything that has the tx_timeout NDO
> must be maintaining trans_start.
So what's your thinking Jay? Keep this as an immediate small fix
for net but work on using a different approach in net-next?
next prev parent reply other threads:[~2022-06-21 19:52 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-16 19:26 [PATCH net] veth: Add updating of trans_start Jay Vosburgh
2022-06-17 10:40 ` patchwork-bot+netdevbpf
2022-06-17 15:45 ` Jakub Kicinski
2022-06-17 16:42 ` Jay Vosburgh
2022-06-17 19:44 ` Jakub Kicinski
2022-06-18 0:27 ` Jay Vosburgh
2022-06-18 0:55 ` Jakub Kicinski
2022-06-21 19:52 ` Jakub Kicinski [this message]
2022-06-22 1:42 ` Jay Vosburgh
2022-06-22 4:38 ` Jakub Kicinski
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