From: Rodolfo Giometti <giometti@enneenne.com>
To: David Woodhouse <dwmw2@infradead.org>,
Richard Cochran <richardcochran@gmail.com>,
Andrew Lunn <andrew+netdev@lunn.ch>,
"David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
John Stultz <jstultz@google.com>,
Thomas Gleixner <tglx@kernel.org>,
Stephen Boyd <sboyd@kernel.org>,
Miroslav Lichvar <mlichvar@redhat.com>,
linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
Alexander Gordeev <agordeev@linux.ibm.com>
Subject: Re: [PATCH v4 2/4] pps: Drop the !NO_HZ_COMMON dependency from NTP_PPS
Date: Mon, 28 Sep 2026 18:41:35 +0200 [thread overview]
Message-ID: <7098f5d2-043d-464a-82d9-a105e4000c02@enneenne.com> (raw)
In-Reply-To: <fc1ec38dbc3723f7aed73ebf3413e1d81c161228.camel@infradead.org>
On Mon, 2026-09-28 at 14:37 +0100, David Woodhouse wrote:
> But I can *simulate* it, by running a virtual machine with vmclock and
> knowing the precise relationship of counter to real time that I'm
> *telling* it to discipline against — then checking how it did. Your "no
> independent reference anywhere" is my "I'm actually testing the part I
> want to test" :)
What it cannot show is the thing this patch actually enables: hardpps
on a tickless kernel driven by a real PPS source, with its jitter, its
IRQ latency, and the CPU going idle between pulses. If you (or someone
on Cc) can run it for a while with a GPS PPS on a GPIO and report how
the offset converges compared with a tickful kernel, that is the test
I would like to see mentioned in the commit message. If not, please at
least state there that the validation was done with the simulated 4/4
pulse only.
Ciao,
Rodolfo
next prev parent reply other threads:[~2026-09-28 16:44 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-29 20:56 [PATCH v4 0/4] Add ntp_error to clock snapshot, enable NTP_PPS on tickless kernel David Woodhouse
2026-08-29 20:56 ` [PATCH v4 1/4] timekeeping: Apply extrapolated ntp_error to clock snapshots David Woodhouse
2026-08-29 20:57 ` [PATCH v4 2/4] pps: Drop the !NO_HZ_COMMON dependency from NTP_PPS David Woodhouse
2026-09-01 15:35 ` Rodolfo Giometti
2026-09-02 0:13 ` David Woodhouse
2026-09-28 13:37 ` David Woodhouse
2026-09-28 16:41 ` Rodolfo Giometti [this message]
2026-09-28 19:28 ` David Woodhouse
2026-09-29 6:33 ` Rodolfo Giometti
2026-09-29 9:32 ` David Woodhouse
2026-09-29 11:48 ` Rodolfo Giometti
2026-09-29 12:02 ` David Woodhouse
2026-09-30 1:28 ` David Woodhouse
2026-09-30 12:57 ` Rodolfo Giometti
2026-09-30 10:37 ` David Woodhouse
2026-09-30 12:57 ` Rodolfo Giometti
2026-09-30 14:05 ` David Woodhouse
2026-09-30 18:24 ` David Woodhouse
2026-10-01 8:20 ` Rodolfo Giometti
2026-10-01 9:08 ` David Woodhouse
2026-08-29 20:57 ` [PATCH v4 3/4] pps: Always use ktime_get_snapshot_id() for pps_get_ts() David Woodhouse
2026-09-01 15:35 ` Rodolfo Giometti
2026-09-01 23:56 ` David Woodhouse
2026-09-26 20:38 ` David Woodhouse
2026-09-28 7:58 ` Rodolfo Giometti
2026-09-28 12:59 ` David Woodhouse
2026-09-28 16:41 ` Rodolfo Giometti
2026-10-01 13:14 ` Miroslav Lichvar
2026-10-01 15:38 ` David Woodhouse
2026-10-02 7:04 ` Rodolfo Giometti
2026-10-02 9:07 ` David Woodhouse
2026-10-02 12:29 ` David Woodhouse
2026-10-02 13:44 ` David Woodhouse
2026-10-03 11:29 ` David Woodhouse
2026-10-05 9:16 ` Miroslav Lichvar
2026-08-29 20:57 ` [PATCH v4 4/4] [DO NOT MERGE] ptp: ptp_vmclock: Add simulated 1PPS support David Woodhouse
2026-09-01 15:35 ` [PATCH v4 0/4] Add ntp_error to clock snapshot, enable NTP_PPS on tickless kernel Rodolfo Giometti
2026-09-01 23:37 ` David Woodhouse
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