From: Oliver Hartkopp <socketcan@hartkopp.net>
To: Harald Mommer <hmo@opensynergy.com>, linux-can@vger.kernel.org
Subject: Re: MSG_CONFIRM RX messages with SocketCAN known as unreliable under heavy load?
Date: Thu, 24 Jun 2021 20:45:33 +0200 [thread overview]
Message-ID: <4b02188f-b3bd-4e80-5d1c-9ace05f54c1d@hartkopp.net> (raw)
In-Reply-To: <8c76c15d-6252-8af5-01d1-71752cd0cb7b@opensynergy.com>
Hello Harald,
On 24.06.21 17:21, Harald Mommer wrote:
> The device application is closed source, runs under the COQOS hypervisor
> which is also closed source.
What is this 'device application' in the sketch below?
>> Can you sketch a quick block diagram showing guest, host, Virtio device,
>> Virtio driver, etc...
>
> I hope this arrives on the list as is been sent and not garbled:
>
> Guest 2 | Guest3
> ---------------- | ----------------
> ! cangen, ! | ! cangen, !
> ! candump, ! | ! candump, !
> ! cansend ! | ! cansend !
> ! using vcan0 ! | ! using can0 !
> ---------------- | ----------------
> ^ | ^
> ! --------------------- | !
> ! ! Service process ! | !
> ! ! in user space ! | !
> ! ! virtio-can device ! | !
> ! ! forwarding vcan0 ! | !
> ! --------------------- | !
Hopefully not this "Service process in user space" ???
If so, this is a very questionable approach!
To route/forward/manipulate CAN frames between CAN network interfaces
there is a CAN gateway module 'can-gw' which can be controlled over
PF_NETLINK.
The can-gw runs super efficient and fast inside kernel space in the
SOFTIRQ context.
E.g. 22.000 CAN frames/s with 6% sys load on a 2 core i7 from 2012,
here: https://youtu.be/O3eOjfTl1yk?t=89
Just type cangw from the can-utils to get an impression of the powerful
options.
You can even calculate E2E CRCs and XOR checksums after doing content
mods on the fly.
> ! ^ ^ | !
> ! ! ! | !
> --------------------------------------------------
> ! ! Device side ! kernel | Driver side ! kernel
> v v v | v
> ---------------- -------------- | ----------------
> ! Device Linux ! ! HV support ! | ! Driver Linux !
> ! VCan ! ! module ! | ! Virtio CAN !
> ! vcan0 ! ! on device ! | ! can0 !
> ! ! ! side ! | ! !
> ---------------- -------------- | ----------------
> ^ ^ | ^
> ! ! | !
> --------------------------------------------------
> ! ! ! Hypervisor
> v v v
> --------------------------------------------------
> ! COQOS-HV !
> --------------------------------------------------
>
(..)
> can be handled. Need the command line switch anyway now to do experiments.
Now with cangw ?!? ;-)
Regards,
Oliver
next prev parent reply other threads:[~2021-06-24 18:45 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-17 12:22 MSG_CONFIRM RX messages with SocketCAN known as unreliable under heavy load? Harald Mommer
2021-06-18 9:16 ` Marc Kleine-Budde
2021-06-18 18:23 ` Oliver Hartkopp
2021-06-19 21:42 ` Marc Kleine-Budde
2021-06-24 15:21 ` Harald Mommer
2021-06-24 18:45 ` Oliver Hartkopp [this message]
2021-06-28 13:47 ` Harald Mommer
2021-06-25 9:19 ` review of virtio-can (was: Re: MSG_CONFIRM RX messages with SocketCAN known as unreliable under heavy load?) Marc Kleine-Budde
2021-06-29 17:14 ` Harald Mommer
2021-07-14 7:15 ` [virtio-dev] " Michael S. Tsirkin
2021-07-15 16:04 ` Harald Mommer
2021-06-25 9:39 ` MSG_CONFIRM RX messages with SocketCAN known as unreliable under heavy load? Marc Kleine-Budde
2021-06-29 19:39 Harald Mommer
2021-06-30 7:27 ` Oliver Hartkopp
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