Underclocking?

[b1ueskycomp1ex]

I was wondering if it would at all be possible to add an under/overclocking option to the main Wiz Menu (music player, etc.) or if there would be a way to replace the shell with one that does allow this. I figure that the lower the device is clocked with the screen off, the more music playing time you would have, right? How fast do you think the wiz would have to be to play a 128KBPS MP3 file? These are just little thoughts, nothing too serious.

 

[cloudy-cola-corp]

or if there would be a way to replace the shell with one that does allow this. I figure that the lower the device is clocked with the screen off, the more music playing time you would have, right? How fast do you think the wiz would have to be to play a 128KBPS MP3 file? These are just little thoughts, nothing too serious.

For the GP2x there was an alternate shell called gmenu2x, it could launch the GP2x's media players and such. But the feature you enquired about, the clock speed, could be set for each app, so for something less powerful you could underclock. I'm hoping this gets ported.

I don' t think clock speed is likely to be added to the official menu though

 

[aho]

A lower clock speed won't extend the battery's run time much if the CPU is idle for the most part anyways, I'd say. Just like your desktop's or laptop's CPU the CPU in the Wiz will take very little energy when idle (3% usage=idle for 97% of the time). The only difference is that those embedded CPUs like Wiz's ARM are even more optimized for low energy consumption.

My rule of thumb guesstimeate is 5 minutes. At most.

 

[sam fisher]

The reason laptop's last longer when not doing anything that they underclock when they aren't. It is called clockspeed scaling and they do it with other hardware such as GPU's too.

 

[aho]

The reason laptop's last longer when not doing anything that they underclock when they aren't. It is called clockspeed scaling and they do it with other hardware such as GPU's too.

There are several sleep modes. E.g. HLT is the cheapest one, which is used whenever you aren't using 100% CPU (unless you're running DOS or Win9x). IIRC there are currently up to 6 or 7.

If something like Cool'n'Quiet/SpeedStep/PowerNow/etc (dynamic frequency scaling) would have been worth it on this kind of architecture I'm sure they would have implemented it. Low energy consumption is very important in this segment after all.

Now that I looked around a bit more... seems like it's actually worth it. ARM9 and newer models seem to support it. If the voltage is also regulated it saves up to 15-20%. Frequency alone won't even save half of that though.

 

[Exophase]

. The only difference is that those embedded CPUs like Wiz's ARM are even more optimized for low energy consumption.

My rule of thumb guesstimeate is 5 minutes. At most.

I thought the same thing, but that's not really always true - I've seen CPUs where idle time saves you almost nothing and lower clocks saves a ton. That aside, a lot of GP2X software doesn't do any wait synchronization and instead polls, especially if the wait for vsync because there's no way to sleep/wait for vsync interrupt without writing a kernel module for it.

 

[b1ueskycomp1ex]

I was thinking some sort of way to set the clock speed lower and run the music player with the lower clock speed, to conserve battery power, considering that it probably doesn't require the full 533Mhz to play an mp3 file, but I'm not so sure.

 

[Knoxximus]

I was thinking some sort of way to set the clock speed lower and run the music player with the lower clock speed, to conserve battery power, considering that it probably doesn't require the full 533Mhz to play an mp3 file, but I'm not so sure.

Shhhhh....dude, they know. Don't interrupt the think tank.

 

[Squidge]

Or maybe we can run at the full 533Mhz and once there is no more work to do (waiting on an event), we can put the processor into halt mode until there is. That could even go in the kernel which knows these things, and then you can run other program at the same time without having to faff around with clock speeds.