From: Henrik Austad <henrik@austad.us>
To: John Fastabend <john.fastabend@gmail.com>
Cc: Richard Cochran <richardcochran@gmail.com>,
linux-kernel@vger.kernel.org, linux-media@vger.kernel.org,
alsa-devel@vger.kernel.org, netdev@vger.kernel.org,
henrik@austad.us, Arnd Bergmann <arnd@linaro.org>
Subject: Re: [very-RFC 0/8] TSN driver for the kernel
Date: Tue, 14 Jun 2016 10:35:55 +0200 [thread overview]
Message-ID: <20160614083555.GA21689@sisyphus.home.austad.us> (raw)
In-Reply-To: <575ED7BC.4000803@gmail.com>
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On Mon, Jun 13, 2016 at 08:56:44AM -0700, John Fastabend wrote:
> On 16-06-13 04:47 AM, Richard Cochran wrote:
> > [...]
> > Here is what is missing to support audio TSN:
> >
> > * User Space
> >
> > 1. A proper userland stack for AVDECC, MAAP, FQTSS, and so on. The
> > OpenAVB project does not offer much beyond simple examples.
> >
> > 2. A user space audio application that puts it all together, making
> > use of the services in #1, the linuxptp gPTP service, the ALSA
> > services, and the network connections. This program will have all
> > the knowledge about packet formats, AV encodings, and the local HW
> > capabilities. This program cannot yet be written, as we still need
> > some kernel work in the audio and networking subsystems.
> >
> > * Kernel Space
> >
> > 1. Providing frames with a future transmit time. For normal sockets,
> > this can be in the CMESG data. For mmap'ed buffers, we will need a
> > new format. (I think Arnd is working on a new layout.)
> >
> > 2. Time based qdisc for transmitted frames. For MACs that support
> > this (like the i210), we only have to place the frame into the
> > correct queue. For normal HW, we want to be able to reserve a time
> > window in which non-TSN frames are blocked. This is some work, but
> > in the end it should be a generic solution that not only works
> > "perfectly" with TSN HW but also provides best effort service using
> > any NIC.
> >
>
> When I looked at this awhile ago I convinced myself that it could fit
> fairly well into the DCB stack (DCB is also part of 802.1Q). A lot of
> the traffic class to queue mappings and priories could be handled here.
> It might be worth taking a look at ./net/sched/mqprio.c and ./net/dcb/.
Interesting, I'll have a look at dcb and mqprio, I'm not familiar with
those systems. Thanks for pointing those out!
I hope that the complexity doesn't run crazy though, TSN is not aimed at
datacentra, a lot of the endpoints are going to be embedded devices,
introducing a massive stack for handling every eventuality in 802.1q is
going to be counter productive.
> Unfortunately I didn't get too far along but we probably don't want
> another mechanism to map hw queues/tcs/etc if the existing interfaces
> work or can be extended to support this.
Sure, I get that, as long as the complexity for setting up a link doesn't
go through the roof :)
Thanks!
--
Henrik Austad
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next prev parent reply other threads:[~2016-06-14 8:36 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-11 23:01 [very-RFC 0/8] TSN driver for the kernel Henrik Austad
2016-06-11 23:01 ` [very-RFC 1/8] TSN: add documentation Henrik Austad
2016-06-11 23:01 ` [very-RFC 2/8] TSN: Add the standard formerly known as AVB to the kernel Henrik Austad
2016-06-11 23:01 ` [very-RFC 3/8] Adding TSN-driver to Intel I210 controller Henrik Austad
2016-06-11 23:01 ` [very-RFC 4/8] Add TSN header for the driver Henrik Austad
2016-06-11 23:01 ` [very-RFC 5/8] Add TSN machinery to drive the traffic from a shim over the network Henrik Austad
2016-06-11 23:01 ` [very-RFC 6/8] Add TSN event-tracing Henrik Austad
2016-06-12 16:58 ` Steven Rostedt
2016-06-12 21:25 ` Henrik Austad
2016-06-13 2:22 ` Steven Rostedt
2016-06-13 7:20 ` Henrik Austad
2016-06-11 23:01 ` [very-RFC 7/8] AVB ALSA - Add ALSA shim for TSN Henrik Austad
2016-06-15 11:49 ` Richard Cochran
2016-06-15 12:13 ` Henrik Austad
2016-06-15 12:43 ` Richard Cochran
2016-06-11 23:01 ` [very-RFC 8/8] MAINTAINERS: add TSN/AVB-entries Henrik Austad
2016-06-13 11:47 ` [very-RFC 0/8] TSN driver for the kernel Richard Cochran
2016-06-13 13:00 ` Henrik Austad
2016-06-13 19:32 ` Richard Cochran
2016-06-14 9:30 ` Henrik Austad
2016-06-14 18:26 ` Richard Cochran
2016-06-14 20:38 ` Henrik Austad
2016-06-15 7:04 ` Richard Cochran
2016-06-15 7:50 ` Henrik Austad
2016-06-15 11:41 ` Richard Cochran
2016-06-15 7:11 ` Richard Cochran
2016-06-13 19:37 ` Richard Cochran
2016-06-13 13:12 ` Arnd Bergmann
2016-06-13 15:56 ` John Fastabend
2016-06-14 8:35 ` Henrik Austad [this message]
2016-06-13 19:51 ` Richard Cochran
2016-06-14 11:18 ` One Thousand Gnomes
2016-06-14 17:04 ` Richard Cochran
2016-06-15 3:15 ` Takashi Sakamoto
2016-06-15 8:06 ` Richard Cochran
2016-06-18 5:22 ` Takashi Sakamoto
2016-06-18 22:45 ` Henrik Austad
2016-06-19 9:46 ` Richard Cochran
2016-06-20 8:05 ` Henrik Austad
2016-06-20 11:08 ` [alsa-devel] " Pierre-Louis Bossart
2016-06-20 11:49 ` Henrik Austad
2016-06-20 12:18 ` Richard Cochran
2016-06-20 12:31 ` Richard Cochran
2016-06-20 15:21 ` Richard Cochran
2016-06-21 5:54 ` Takashi Iwai
2016-06-21 6:38 ` Richard Cochran
2016-06-21 6:45 ` Takashi Iwai
2016-06-21 17:18 ` Pierre-Louis Bossart
2016-06-21 17:45 ` Pierre-Louis Bossart
2016-06-21 19:40 ` Richard Cochran
2016-06-22 12:36 ` Pierre-Louis Bossart
2016-06-23 10:38 ` Henrik Austad
2016-06-23 13:28 ` Richard Cochran
2016-06-15 3:27 ` Takashi Sakamoto
-- strict thread matches above, loose matches on Subject: below --
2016-06-11 22:22 Henrik Austad
2016-06-11 22:49 ` Henrik Austad
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