[mythtv] [mythtv-commits] Ticket #2782: automatic simultaneous jobs scaling

[osma ahvenlampi]

On 12/8/06, Michael T. Dean <mtdean at thirdcontact.com> wrote:
> The idle value /never/ changes on any of the hosts, thanks to a little
> program I call AthWarm (most call SETI/BOINC).  :)

Ah, I didn't consider someone wanting to run their HTPC hot - I've
been more concerned about running it quiet. How would you propose
detecting between time spent in SETI vs time spent by jobs? The kernel
won't distinguish between the niced processes..

> No problem, though, I wouldn't mind disabling job scaling.  (Now,
> disabling BOINC, OTOH, will not happen :).

I didn't make this configurable, because I would have liked to make it
"work right" without configuring. That can be done though, but I'd
rather figure out a better solution.

> This will happen even without encoding video (i.e. even with DVB or
> HDTV) if I/O wait becomes "critical".

It *can* happen, but *will* it? With 2.6.15+ and CFQ I/O queues, I
can't see it being very realistic. Does anyone have empiric proof? On
Linux or some other system?

At least one change would need to happen for this to become
commit-worthy, I guess: right now jobqueue will not start *any*
processes if there's no idle time, but it will start them if it can't
read idle time at all. I'll change it so that it will start *one*
process in either of those situations, but scale up from there only if
there's still time available. Would that be satisfactory?

-- 
Osma Ahvenlampi   <oa at iki.fi>       http://www.fishpool.org