[linux-audio-user] Re: [Jackit-devel] [ANN] das_watchdog 0.0.1 and jack_capture v0.2.3

From: Kjetil Svalastog Matheussen <kjetil@email-addr-hidden>
Date: Mon Feb 13 2006 - 22:05:55 EET

On Mon, 13 Feb 2006, Florian Schmidt wrote:

> On Sun, 12 Feb 2006 20:46:08 -0800 (PST)
> "Kjetil S. Matheussen" <kjetil@email-addr-hidden> wrote:
>
>> Das_Watchdog
>> ============
>>
>> ABOUT
>> -----
>> Das_Watchdog is a program heavily and shamefully inspired by the
>> rt_watchdog program made by Florian Schmidt:
>> http://tapas.affenbande.org/?page_id=38
>
> Hehe, why shamefully? This is open source, baby. So i'm glad there's
> some alternative to my messy code ;) And btw: the two programs are still
> a bit different. rt_watchdog is a daemon. I have wondered about how to
> make it known to the user that it has kicked in. The only solution i
> found was to write into the logs. Opening an xwindow is an interesting
> solution. Does linux maybe even have a standardized way for this kinda
> stuff?
>

Don't know. It should. Actually, I did not try the program very hard
before releasing, so starting the program outside X won't start the
program. X just refuse connection...

I eventually found a work-around though, but it involves setting up
password-less ssh connection for root (secure, but its a bit work to set
up), and let an X-program run "xhost local:root" after X has started. Not
very nice, but it works.

>> However, this one has some improvements:
>>
>> 1. It works with 2.4 kernels as well as 2.6. (well, at least I think it
>> works with 2.6...)
>> 2. Instead of permanently setting all realtime processes to run
>> non-realtime, das_watchdog only sets them temporary.
>> 3. When the watchdog kicks in, an X window should pop up that tells you
>> whats happening. (just close it after reading the message).
>>
>>
>> INSTALLING
>> ----------
>> make
>> cp das_watchdog /usr/local/sbin/
>> echo '/usr/local/sbin/das_watchdog & >/dev/null' >>/etc/rc.local
>
> This assumes an initscript style that's not used on all linux systems.
>

Well, this was just an example. /etc/rc.sysinit can also be used.

>> reboot
>
> Also i wonder: Is it safe to simply use a static int as "event counter"?

Yes.

> Might this not fail on SMP boxes?
>

Nope, its safe. One thread increases the variable, and another check that
it has been increased. If that fails, something is wrong with the
machine.
Received on Tue Feb 14 00:15:07 2006

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