netdev - Re: [PATCH v6 net-next 3/4] net: ena: Add PHC documentation

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20250210164358.11091722@kernel.org>
Date: Mon, 10 Feb 2025 16:43:58 -0800
From: Jakub Kicinski <kuba@...nel.org>
To: "Arinzon, David" <darinzon@...zon.com>
Cc: David Miller <davem@...emloft.net>, "netdev@...r.kernel.org"
 <netdev@...r.kernel.org>, Eric Dumazet <edumazet@...gle.com>, Paolo Abeni
 <pabeni@...hat.com>, Simon Horman <horms@...nel.org>, Richard Cochran
 <richardcochran@...il.com>, "Woodhouse, David" <dwmw@...zon.co.uk>,
 "Machulsky, Zorik" <zorik@...zon.com>, "Matushevsky, Alexander"
 <matua@...zon.com>, "Bshara, Saeed" <saeedb@...zon.com>, "Wilson, Matt"
 <msw@...zon.com>, "Liguori, Anthony" <aliguori@...zon.com>, "Bshara, Nafea"
 <nafea@...zon.com>, "Schmeilin, Evgeny" <evgenys@...zon.com>, "Belgazal,
 Netanel" <netanel@...zon.com>, "Saidi, Ali" <alisaidi@...zon.com>,
 "Herrenschmidt, Benjamin" <benh@...zon.com>, "Kiyanovski, Arthur"
 <akiyano@...zon.com>, "Dagan, Noam" <ndagan@...zon.com>, "Bernstein, Amit"
 <amitbern@...zon.com>, "Agroskin, Shay" <shayagr@...zon.com>, "Abboud,
 Osama" <osamaabb@...zon.com>, "Ostrovsky, Evgeny" <evostrov@...zon.com>,
 "Tabachnik, Ofir" <ofirt@...zon.com>, "Machnikowski, Maciek"
 <maciek@...hnikowski.net>, Rahul Rameshbabu <rrameshbabu@...dia.com>, Gal
 Pressman <gal@...dia.com>
Subject: Re: [PATCH v6 net-next 3/4] net: ena: Add PHC documentation

On Mon, 10 Feb 2025 15:28:19 +0000 Arinzon, David wrote:
> You are right in the regard that it is not a network specific functionality.
> Having said that, PHC is a network card capability, making it a network-related component rather than purely a timekeeping feature.
> Moreover we failed to find an existing tool which would allow users to get valuable feedback of the system's overall health.
> 
> Researching its existing support in the kernel we noted that:
> - PHC is embedded in network NIC and is supported by multiple NIC vendors in the kernel
> - PHC information is visible through ethtool -T
> - The Linux networking stack uses PHC for timekeeping as well as for packet timestamping (via SO_TIMESTAMPING).
>   Packet timestamping statistics are available through ethtool get_ts_stats hook
> 
> We have found `ethtool -S` as a suitable location for exposing these statistics, which are unique to the ENA NIC.
> 
> We'd appreciate your thoughts on the matter, is there an alternative tool you can recommend?

We try to steer folks towards read-only debugfs files for stuff
that's not strictly networking related. You also add a custom
sysfs file in patch 4, I reckon adding stats there may also be
a natural place for the user? 

Patch 4 FWIW is lacking slightly in the justification, would 
be good to clarify why it's disabled by default. Single sentence
of "why" would be great.