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mcruz
14 Posts |
 Posted - 12 Mar 2003 : 09:12:58
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| What is the voltage/freq scaling latency for the (StrongArm & Xscale)Bitsy Plus, Graphics Client Plus, and Graphics Master? Is it measured overall in microseconds, milliseconds? Does this scaling affect the system operations? Does an OS make a difference (Win CE vs. Linux) in latency time? |
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akidder
1519 Posts |
Posted - 12 Mar 2003 : 11:35:30
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Our systems put the processor into Idle mode (core temporarily inactive) when the processor core isn't needed for a task. This is handled automatically by the OS. Likewise, on XScale systems, applications can change the processor mode so that it will run in Turbo mode instead of Run mode.
Here are OS-specific details:
Windows CE
CE puts the CPU into Idle mode when running the Idle process. Use \Windows\Turbo.exe to put ADS XScale systems into Turbo mode instead of the standard Run mode.
Linux
When no task is scheduled, the Linux scheduler waits in Idle mode for an interrupt. Applications/tasks normally are executed in Run mode, but the processor can be set programmatically to operate in Turbo mode instead.
Latency in switching between these modes isn't typcially a issue for most applications. If you have an application for which you think this latency will be an issue, feel free to contact us with details of your application requirements. |
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tbronez
17 Posts |
Posted - 03 Mar 2005 : 11:43:52
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I've executed \Windows\TurboMode.exe on my WinCE 4.2 BitsyX. However, there is no way of telling if the mode actually changed from Run to Turbo. Additionally, there is apparently no way to change back to Run mode.
Can you provide a description and source code for TurboMode.exe?
Also, is there a hook to determine the current mode of the processor?
Finally, can you tell us what OEM-specific customizations, if any, you have implemented in the Power Manager (pm.dll)?
Thanks. |
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tbronez
17 Posts |
Posted - 03 Mar 2005 : 11:47:20
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I've executed \Windows\TurboMode.exe on my WinCE 4.2 BitsyX. However, there is no way of telling if the mode actually changed from Run to Turbo. Additionally, there is apparently no way to change back to Run mode.
Can you provide a description and source code for TurboMode.exe?
Also, is there a hook to determine the current mode of the processor?
Finally, can you tell us what OEM-specific customizations, if any, you have implemented in the Power Manager (pm.dll)?
Thanks. |
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