From: Thomas Gleixner <tglx@kernel.org>
To: David Woodhouse <dwmw2@infradead.org>,
LKML <linux-kernel@vger.kernel.org>
Cc: Miroslav Lichvar <mlichvar@redhat.com>,
John Stultz <jstultz@google.com>, Stephen Boyd <sboyd@kernel.org>,
Anna-Maria Behnsen <anna-maria@linutronix.de>,
Frederic Weisbecker <frederic@kernel.org>,
thomas.weissschuh@linutronix.de,
Arthur Kiyanovski <akiyano@amazon.com>,
Rodolfo Giometti <giometti@enneenne.com>,
Vincent Donnefort <vdonnefort@google.com>,
Marc Zyngier <maz@kernel.org>,
Oliver Upton <oliver.upton@linux.dev>,
kvmarm@lists.linux.dev, Oliver Upton <oupton@kernel.org>,
Richard Cochran <richardcochran@gmail.com>,
netdev@vger.kernel.org, Takashi Iwai <tiwai@suse.com>,
Miri Korenblit <miriam.rachel.korenblit@intel.com>,
Johannes Berg <johannes.berg@intel.com>,
Jacob Keller <jacob.e.keller@intel.com>,
Tony Nguyen <anthony.l.nguyen@intel.com>,
Saeed Mahameed <saeedm@nvidia.com>,
Peter Hilber <peter.hilber@oss.qualcomm.com>,
"Michael S. Tsirkin" <mst@redhat.com>,
virtualization@lists.linux.dev, linux-wireless@vger.kernel.org,
linux-sound@vger.kernel.org,
Vadim Fedorenko <vadim.fedorenko@linux.dev>
Subject: Re: [patch V2 18/25] timekeeping: Prepare for cross timestamps on arbitrary clock IDs
Date: Mon, 22 Jun 2026 13:07:46 +0200 [thread overview]
Message-ID: <87se6eltod.ffs@fw13> (raw)
In-Reply-To: <b296182e2e2c1ed2fe1c4879fd6f12d67a7ad22f.camel@infradead.org>
On Mon, Jun 22 2026 at 09:55, David Woodhouse wrote:
> On Fri, 2026-05-29 at 22:01 +0200, Thomas Gleixner wrote:
>> From: Thomas Gleixner <tglx@kernel.org>
>>
>> PTP device system crosstime stamps support only CLOCK_REALTIME, which is
>> meaningless for AUX clocks. The PTP core hands in the clock ID already, so
>> prepare the core code to honor it.
>>
>> - Add a new sys_systime field to struct system_device_crosststamp which
>> aliases the sys_realtime field. Once all users are converted
>> sys_realtime can be removed.
>>
>> - Prepare get_device_system_crosststamp() and the related code for it by
>> switching to sys_systime and providing the initial changes to utilize
>> different time keepers.
>>
>> No functional change intended.
>
> We ended up with ktime_get_snapshot_id() also supporting CLOCK_BOOTTIME
> and CLOCK_MONOTONIC_RAW, but not get_device_system_crosststamp().
> Should we make that consistent?
Maybe. The BOOTTIME support is only there for that ARM64 hyper trace muck,
but has no other relevance.
MONORAW is there for the PTP EXTENDED IOCTL, but with PRECISE the
snapshot already contains the raw value and you'd have to prevent the
historical adjustment part for RAW. So I don't see the actual value, but
I don't have a strong opinion either.
Thanks,
tglx
next prev parent reply other threads:[~2026-06-22 11:07 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-29 19:59 [patch V2 00/25] timekeeping/ptp: Expand snapshot functionality Thomas Gleixner
2026-05-29 19:59 ` [patch V2 01/25] timekeeping: Provide ktime_get_snapshot_id() Thomas Gleixner
2026-05-29 19:59 ` [patch V2 02/25] timekeeping: Use system_time_snapshot::systime/monoraw instead of ::real/raw Thomas Gleixner
2026-05-29 19:59 ` [patch V2 03/25] pps: generators: Use ktime_get_real_ts64() instead of ktime_get_snapshot() Thomas Gleixner
2026-05-30 11:04 ` Rodolfo Giometti
2026-05-29 20:00 ` [patch V2 04/25] pps: Convert to ktime_get_snapshot_id() Thomas Gleixner
2026-05-30 11:08 ` Rodolfo Giometti
2026-06-02 9:31 ` Thomas Gleixner
2026-06-02 10:56 ` David Woodhouse
2026-05-29 20:00 ` [patch V2 05/25] KVM: arm64: Use ktime_get_snapshot_id() to retrieve CLOCK_BOOTTIME Thomas Gleixner
2026-05-29 20:00 ` [patch V2 06/25] KVM: arm64: Use ktime_get_snapshot_id() to snapshot CLOCK_REALTIME Thomas Gleixner
2026-05-29 20:00 ` [patch V2 07/25] ptp: ptp_vmclock: Convert to ktime_get_snapshot_id() Thomas Gleixner
2026-05-29 20:00 ` [patch V2 08/25] timekeeping: Remove system_time_snapshot::real/boot/raw Thomas Gleixner
2026-05-29 20:00 ` [patch V2 09/25] timekeeping: Add CLOCK_AUX support for ktime_get_snapshot_id() Thomas Gleixner
2026-05-29 20:00 ` [patch V2 10/25] timekeeping: Add system_counterval_t to struct system_device_crosststamp Thomas Gleixner
2026-05-29 20:00 ` [patch V2 11/25] timekeeping: Add CLOCK ID to system_device_crosststamp Thomas Gleixner
2026-05-29 20:00 ` [patch V2 12/25] wifi: iwlwifi: Adopt PTP cross timestamps to core changes Thomas Gleixner
2026-05-29 20:00 ` [patch V2 13/25] ice/ptp: Use provided clock ID for history snapshot Thomas Gleixner
2026-05-29 20:00 ` [patch V2 14/25] igc: " Thomas Gleixner
2026-05-29 20:00 ` [patch V2 15/25] net/mlx5: " Thomas Gleixner
2026-05-29 20:00 ` [patch V2 16/25] virtio_rtc: " Thomas Gleixner
2026-06-02 14:44 ` Peter Hilber
2026-05-29 20:00 ` [patch V2 17/25] timekeeping: Remove ktime_get_snapshot() Thomas Gleixner
2026-05-29 20:01 ` [patch V2 18/25] timekeeping: Prepare for cross timestamps on arbitrary clock IDs Thomas Gleixner
2026-06-22 8:55 ` David Woodhouse
2026-06-22 11:07 ` Thomas Gleixner [this message]
2026-06-22 12:34 ` David Woodhouse
2026-05-29 20:01 ` [patch V2 19/25] ptp: Use system_device_crosststamp::sys_systime Thomas Gleixner
2026-05-29 20:01 ` [patch V2 20/25] wifi: iwlwifi: " Thomas Gleixner
2026-05-29 20:01 ` [patch V2 21/25] ALSA: hda/common: " Thomas Gleixner
2026-06-02 17:46 ` Takashi Iwai
2026-05-29 20:01 ` [patch V2 22/25] timekeeping: Remove system_device_crosststamp::sys_realtime Thomas Gleixner
2026-05-29 20:01 ` [patch V2 23/25] timekeeping: Add support for AUX clock cross timestamping Thomas Gleixner
2026-05-29 20:01 ` [patch V2 24/25] ptp: Switch to ktime_get_snapshot_id() for pre/post timestamps Thomas Gleixner
2026-05-29 20:01 ` [patch V2 25/25] timekeeping: Add clocksource read_snapshot() method and hw_cycles to snapshot Thomas Gleixner
2026-05-29 20:33 ` [patch V2 00/25] timekeeping/ptp: Expand snapshot functionality Jacob Keller
2026-06-01 10:59 ` Michael S. Tsirkin
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