netdev - Re: [PATCH iwl-next v2] igb: Convert Tx timestamping to PTP aux worker

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Message-ID: <878qj4q2pq.fsf@jax.kurt.home>
Date: Wed, 27 Aug 2025 16:05:53 +0200
From: Kurt Kanzenbach <kurt@...utronix.de>
To: Miroslav Lichvar <mlichvar@...hat.com>, Sebastian Andrzej Siewior
 <bigeasy@...utronix.de>
Cc: Jacob Keller <jacob.e.keller@...el.com>, Tony Nguyen
 <anthony.l.nguyen@...el.com>, Przemek Kitszel
 <przemyslaw.kitszel@...el.com>, Andrew Lunn <andrew+netdev@...n.ch>,
 "David S. Miller" <davem@...emloft.net>, Eric Dumazet
 <edumazet@...gle.com>, Jakub Kicinski <kuba@...nel.org>, Paolo Abeni
 <pabeni@...hat.com>, Richard Cochran <richardcochran@...il.com>, Vinicius
 Costa Gomes <vinicius.gomes@...el.com>, Paul Menzel
 <pmenzel@...gen.mpg.de>, Vadim Fedorenko <vadim.fedorenko@...ux.dev>,
 intel-wired-lan@...ts.osuosl.org, netdev@...r.kernel.org
Subject: Re: [PATCH iwl-next v2] igb: Convert Tx timestamping to PTP aux worker

On Wed Aug 27 2025, Miroslav Lichvar wrote:
> On Tue, Aug 26, 2025 at 02:59:12PM +0200, Sebastian Andrzej Siewior wrote:
>> The benchmark is about > 1k packets/ second while in reality you have
>> less than 20 packets a second.
>
> I don't want to argue about which use case is more important, but it's
> normal for NTP servers to receive requests at much higher rates than
> that. In some countries, public servers get hundreds of thousands of
> packets per second. A server in a local network may have clients
> polling 128 times per second each.
>
> Anyway, if anyone is still interested in finding out the cause of
> the regression, there is a thing I forgot to mention for the
> reproducer using ntpperf. chronyd needs to be configured with a larger
> clientloglimit (e.g. clientloglimit 100000000), otherwise it won't be
> able to respond to the large number of clients in interleaved mode
> with a HW TX timestamp.

Yeah, I realized that myself while testing :). The default
clientloglimit is too low.

Thanks,
Kurt

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