Subject: Re: power management and related concerns
To: None <>
From: Garrett D'Amore <>
List: tech-kern
Date: 07/01/2006 08:17:43
Thomas E. Spanjaard wrote:
> Steven M. Bellovin wrote:
>> On Sat, 01 Jul 2006 13:18:27 +0000, "Thomas E. Spanjaard"
>> <> wrote:
>>> Steven M. Bellovin wrote:
>>>>     temp=acpitemp     >70*2       /bin/shutdown -p now
>>>> where the *2 indicates that it has to happen twice in a row.  A few
>>>> more
>>>> frills, like shell variables for each config line -- the 'temp'
>>>> means that
>>>> a script would be run with envstatd_temp set to the value.  A | at the
>>>> start of the command would create a pipeline that would be fed the
>>>> value
>>>> on stdin, to permit easy real-time graphing programs.
>>> Confusing, using mathematical symbols for other meanings. Isn't the
>>> how-many-times-or-how-long (as Jachym Holecek suggested) better off
>>> in a separate column (think inetd.conf syntax)? Come to think of it,
>>> inetd.conf is a viable example format for this.
>> I thought about that; it's certainly one perspective.  Here, though, I
>> assumed that it would rarely be used, in which case I'm imposing a
>> burden
>> on everything else.  The other option is something like '-n 2', but that
>> might be even more confusing.
> Hmm, but a crontab is similar to this as well, but allows you to use *
> in separate columns (so no binary operator use is associated with the
> symbol due to obvious distance between columns) in the case where you
> don't want to specify anything specific.

Rather than go down the path of inventing a new format, why not just put
this in XML.  The code lives in userland, so an XML parser isn't too big
a deal.   Plus you get all the extensibility, etc.

As far as extensible interface from sysmon to powerd, I rather like the
idea of sending property lists, but I would prefer to use some kind of
packed format.  I don't want to force the kernel to pack up XML just to
send messages to userland.

    -- Garrett
> Cheers,

Garrett D'Amore, Principal Software Engineer
Tadpole Computer / Computing Technologies Division,
General Dynamics C4 Systems
Phone: 951 325-2134  Fax: 951 325-2191