[mythtv-users] Stop / Start Athcool just Befor / After a Recording

[Bob]

f-myth-users at media.mit.edu wrote:
> Date: Wed, 23 Nov 2005 12:33:22 -0500From: Erik Karlin <e_karlin at yahoo.com>
>> 
>> you could just hijack the channel change "script" functionality andcreate a user job when the recording completes. The problem ofback-to-back recordings is still possible. maybe some clever filelocking scheme between a channel change (start) and user job (end) coulddo the trick.
> 
> [There's nothing out there that looks at CPU utilization and leaves
> low-power mode if the CPU suddenly looks busy?  Or is the problem
> latency?  Laptops do this kind of CPU cycling all the time...  Or
> is it that the CPU never looks busy, but recordings are messed up
> even so, if done in powersave mode?]

There is CPU frequency scaling for the Athlon 64 users or for laptops, 
the problem is the BIOS on a desktop motherboard doesn't contain the 
necessary PST tables that the list the valid voltage and multiplier 
settings for a given mobile CPU, also most desktop MBs can't change the 
core voltages anyway.

There is an interesting thread on the subject over on the Gentoo forums.
http://forums.gentoo.org/viewtopic-t-183519-postdays-0-postorder-asc-start-0.html 


There is an apparently working patch for powernow-k7.c (the kernel 
module that does cpu frequency scaling for Athlon XP-Ms) to stop it 
using the ACPI tables of CPU-modes, and instead use a user supplied 
table. There is also a suggestion that the ability to supply your own 
PST table may be included in the vanilla kernel at some point.

The problem is that without voltage scaling, frequency scaling doesn't 
save *that* much power, and Athcool uses different techniques.

I'm trying to get my system as efficient as possible, I use nvclock to 
underclock my GPU and I'd like to use Athcool and the modified powernow 
module. I'm looking for ways to get nvclock to vary my GPU speed 
depending on if the system is idle or playing games or content, and turn 
off Athcool when recording and probably when playing games or content also.

After that all I need is disk-less front ends and spin-down hard-drives 
in the backend and I'll be happy, I'm moving in 3 weeks so all that will 
have to wait till January.

> Here's a totally gross idea, but it might work, and could be done with
> a tiny shell script.  Assume we start from the powersave state.  The
> script loops, once per second, checking the mod-date of the recordings
> directory itself.  If it changes, immediately go to non-powersave state.

Eww, I felt dirty just reading that.

8< snip

> It would definitely be better if there were hooks for MythTV actions,
> though, since using an event-driven style to control this would be
> much more reliable and less of a kluge than the polling method above.

Agreed

-- 
tveeprom: Hauppauge: model = 34132, rev = J158,
tveeprom: tuner = Philips FM1236 MK3 (idx = 58, type = 4)
tveeprom: audio_processor = MSP3416 (type = 14)
(new type Model 401)
model name      : mobile AMD Athlon(tm) XP Processor
cpu MHz         : 2277.214
cache size      : 512 KB
(Plenty o' grunt on an ECS k7s5a MB)
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