From: Matt Corallo <ntp-lists@mattcorallo.com>
To: Richard Cochran <richardcochran@gmail.com>,
Miroslav Lichvar <mlichvar@redhat.com>
Cc: chrony-dev@chrony.tuxfamily.org,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>
Subject: Re: [chrony-dev] Support for Multiple PPS Inputs on single PHC
Date: Thu, 23 Feb 2023 12:56:34 -0800 [thread overview]
Message-ID: <5bfd4360-2bee-80c1-2b46-84b97f5a039c@bluematt.me> (raw)
In-Reply-To: <Y/OQkNJQ6CP+FaIT@hoboy.vegasvil.org>
On 2/20/23 7:24 AM, Richard Cochran wrote:
> On Mon, Feb 20, 2023 at 11:08:23AM +0100, Miroslav Lichvar wrote:
>> Does it need to be that way? It seems strange for the kernel to
>> support enabling PPS on multiple channels at the same time, but not
>> allow multiple applications to receive all samples from their channel.
>
> It does not need to be that way, but nobody ever wanted multiple
> readers before.
>
> Implementing this would make the kernel side much more complex, as the
> code would need per-reader tracking of the buffered time stamps, or
> per-reader fifo buffers, etc.
There's two separate questions here - multiple readers receiving the same data, and multiple readers
receiving data exclusively about one channel.
I'd imagine the second is (much?) easier to implement, whereas the first is a bunch of complexity.
At least personally I'm okay with the second, rather than the first, and that fixes the issue for
chrony, though it doesn't allow one to, say, get raw samples in one program while having another
handle them.
Matt
next prev parent reply other threads:[~2023-02-23 20:56 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <72ac9741-27f5-36a5-f64c-7d81008eebbc@bluematt.me>
[not found] ` <Y+3m/PpzkBN9kxJY@localhost>
2023-02-16 17:54 ` [chrony-dev] Support for Multiple PPS Inputs on single PHC Matt Corallo
2023-02-16 22:54 ` Richard Cochran
2023-02-17 0:58 ` Matt Corallo
2023-02-20 10:08 ` Miroslav Lichvar
2023-02-20 15:24 ` Richard Cochran
2023-02-23 20:56 ` Matt Corallo [this message]
2023-02-24 0:19 ` Richard Cochran
2023-02-24 1:18 ` Matt Corallo
2023-02-24 5:07 ` Richard Cochran
2023-08-29 11:47 ` Xabier Marquiegui
2023-08-29 11:47 ` [PATCH] ptp: Demultiplexed timestamp channels Xabier Marquiegui
2023-08-29 14:07 ` Richard Cochran
2023-08-29 14:15 ` Richard Cochran
2023-08-30 21:41 ` [chrony-dev] Support for Multiple PPS Inputs on single PHC Xabier Marquiegui
2023-08-30 21:41 ` [PATCH] ptp: Demultiplexed timestamp channels Xabier Marquiegui
2023-08-30 22:01 ` Richard Cochran
2023-09-06 10:47 ` Xabier Marquiegui
2023-09-06 10:47 ` [PATCH 1/3] ptp: Replace timestamp event queue with linked list Xabier Marquiegui
2023-09-06 10:47 ` [PATCH 2/3] ptp: support multiple timestamp event readers Xabier Marquiegui
2023-09-06 18:13 ` Simon Horman
2023-09-06 22:13 ` kernel test robot
2023-09-06 10:47 ` [PATCH 3/3] ptp: support event queue reader channel masks Xabier Marquiegui
2023-09-06 18:18 ` kernel test robot
2023-08-31 0:29 ` [PATCH] ptp: Demultiplexed timestamp channels kernel test robot
2023-08-31 13:28 ` kernel test robot
2023-08-31 16:20 ` kernel test robot
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