From: Jakub Kicinski <kuba@kernel.org>
To: Vladimir Oltean <vladimir.oltean@nxp.com>
Cc: "Russell King (Oracle)" <linux@armlinux.org.uk>,
"Andrew Lunn" <andrew@lunn.ch>,
"Köry Maincent" <kory.maincent@bootlin.com>,
netdev@vger.kernel.org, glipus@gmail.com,
maxime.chevallier@bootlin.com, vadim.fedorenko@linux.dev,
richardcochran@gmail.com, gerhard@engleder-embedded.com,
thomas.petazzoni@bootlin.com, krzysztof.kozlowski+dt@linaro.org,
robh+dt@kernel.org, "Jacob Keller" <jacob.e.keller@intel.com>,
"Zulkifli,
Muhammad Husaini" <muhammad.husaini.zulkifli@intel.com>
Subject: Re: [PATCH net-next RFC v4 2/5] net: Expose available time stamping layers to user space.
Date: Fri, 19 May 2023 13:22:50 -0700 [thread overview]
Message-ID: <20230519132250.35ce4880@kernel.org> (raw)
In-Reply-To: <20230519132802.6f2v47zuz7omvazy@skbuf>
On Fri, 19 May 2023 16:28:02 +0300 Vladimir Oltean wrote:
> > I may have lost track of what the argument is. There are devices
> > which will provide a DMA stamp for Tx and Rx. We need an API that'll
> > inform the user about it.
> >
> > To be clear I'm talking about drivers which are already in the tree,
> > not opening the door for some shoddy new HW in.
>
> So this is circling back to my original question (with emphasis on the
> last part):
>
> | Which drivers provide DMA timestamps, and how do they currently signal
> | that they do this? Do they do this for all packets that get timestamped,
> | or for "some"?
>
> https://lore.kernel.org/netdev/20230511203646.ihljeknxni77uu5j@skbuf/
>
> If only "some" packets (unpredictable which) get DMA timestamps when
> a MAC timestamp isn't available, what UAPI can satisfactorily describe
> that? And who would want that?
The short answer is "I don't know". There's been a lot of talk about
time stamps due to Swift/BBRv2, but I don't have first hand experience
with it. That'd require time stamping "all" packets but the precision
is really only required to be in usec.
Maybe Muhammad has a clearer use case in mind.
next prev parent reply other threads:[~2023-05-19 20:22 UTC|newest]
Thread overview: 79+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-04-06 17:33 [PATCH net-next RFC v4 0/5] net: Make MAC/PHY time stamping selectable Köry Maincent
2023-04-06 17:33 ` [PATCH net-next RFC v4 1/5] net: ethtool: Refactor identical get_ts_info implementations Köry Maincent
2023-04-12 13:16 ` Vladimir Oltean
2023-04-12 13:49 ` Köry Maincent
2023-04-12 16:56 ` Richard Cochran
2023-04-06 17:33 ` [PATCH net-next RFC v4 2/5] net: Expose available time stamping layers to user space Köry Maincent
2023-04-07 1:46 ` Jakub Kicinski
2023-04-07 8:58 ` Köry Maincent
2023-04-07 14:26 ` Jakub Kicinski
2023-04-07 14:44 ` Jakub Kicinski
2023-05-17 19:58 ` Jacob Keller
2023-04-12 10:50 ` Michael Walle
2023-04-12 11:08 ` Vladimir Oltean
2023-04-12 11:12 ` Michael Walle
2023-04-12 12:19 ` Köry Maincent
2023-05-11 20:36 ` Vladimir Oltean
2023-05-11 20:50 ` Andrew Lunn
2023-05-11 20:55 ` Russell King (Oracle)
2023-05-11 21:02 ` Vladimir Oltean
2023-05-11 22:09 ` Jakub Kicinski
2023-05-11 23:07 ` Vladimir Oltean
2023-05-11 23:16 ` Jakub Kicinski
2023-05-12 10:29 ` Vladimir Oltean
2023-05-12 17:38 ` Jakub Kicinski
2023-05-17 19:19 ` Jakub Kicinski
2023-05-17 19:46 ` Andrew Lunn
2023-05-17 20:07 ` Jakub Kicinski
2023-09-04 15:22 ` Köry Maincent
2023-09-04 17:47 ` Richard Cochran
2023-09-05 18:47 ` Jakub Kicinski
2023-09-05 20:29 ` Andrew Lunn
2023-09-06 9:22 ` Köry Maincent
2023-09-07 9:29 ` Russell King (Oracle)
2023-05-19 13:28 ` Vladimir Oltean
2023-05-19 20:22 ` Jakub Kicinski [this message]
2023-05-22 3:56 ` Zulkifli, Muhammad Husaini
2023-05-22 20:04 ` Richard Cochran
2023-05-22 20:21 ` Jakub Kicinski
2023-05-23 3:54 ` Richard Cochran
2023-05-17 22:01 ` Jacob Keller
2023-05-17 22:13 ` Jacob Keller
2023-05-17 22:46 ` Richard Cochran
2023-05-18 23:23 ` Jacob Keller
2023-05-19 12:50 ` Andrew Lunn
2023-05-19 13:50 ` Richard Cochran
2023-05-19 15:18 ` Andrew Lunn
2023-04-08 14:06 ` Richard Cochran
2023-04-06 17:33 ` [PATCH net-next RFC v4 3/5] dt-bindings: net: phy: add timestamp preferred choice property Köry Maincent
2023-04-12 13:14 ` Vladimir Oltean
2023-04-12 13:44 ` Köry Maincent
2023-04-29 17:42 ` Vladimir Oltean
2023-05-02 9:10 ` Köry Maincent
2023-05-11 13:10 ` Vladimir Oltean
2023-05-11 13:25 ` Köry Maincent
2023-05-11 13:56 ` Vladimir Oltean
2023-05-11 14:22 ` Köry Maincent
2023-04-12 14:14 ` Krzysztof Kozlowski
2023-04-06 17:33 ` [PATCH net-next RFC v4 4/5] net: Let the active time stamping layer be selectable Köry Maincent
2023-04-06 20:04 ` kernel test robot
2023-04-07 1:02 ` kernel test robot
2023-04-07 1:47 ` Jakub Kicinski
2023-04-07 2:04 ` kernel test robot
2023-04-29 17:58 ` Vladimir Oltean
2023-05-02 11:05 ` Köry Maincent
2023-05-11 13:48 ` Vladimir Oltean
2023-05-11 15:36 ` Jakub Kicinski
2023-05-11 15:56 ` Vladimir Oltean
2023-05-11 16:25 ` Jakub Kicinski
2023-05-11 20:54 ` Vladimir Oltean
2023-05-11 23:08 ` Jakub Kicinski
2023-05-11 23:18 ` Vladimir Oltean
2023-05-11 23:35 ` Jakub Kicinski
2023-05-15 9:04 ` Köry Maincent
2023-05-16 19:28 ` Jakub Kicinski
2023-05-11 21:06 ` Russell King (Oracle)
2023-05-11 22:54 ` Jakub Kicinski
2023-05-17 22:19 ` Jacob Keller
2023-04-06 17:33 ` [PATCH net-next RFC v4 5/5] net: fix up drivers WRT phy time stamping Köry Maincent
2023-04-06 17:59 ` [PATCH net-next RFC v4 0/5] net: Make MAC/PHY time stamping selectable Köry Maincent
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