Re: detecting hard disk idleness

[Richard B. Johnson]

On Wed, 21 Aug 2002, Mukesh Rajan wrote:

> this again would mean that i would have to poll the /proc/interrupt file.
> i want to avoid polling because of very small poll interval causing
> overhead. i am still wondering if this could be implemented with some sort
> of interrupt mechanism in linux (kernel interrupting user program or user
> program waiting on some signal)
> 
> - mukesh
> 

Hard disk 'idleness' is something you would check at a 1-second
interval. As such, its overhead is very small.

This is a sample at 1 second intervals during a kernel compile:

 11:       4667       4585   IO-APIC-level  BusLogic BT-958
 11:       4667       4585   IO-APIC-level  BusLogic BT-958
 11:       4667       4585   IO-APIC-level  BusLogic BT-958
 11:       4667       4585   IO-APIC-level  BusLogic BT-958
 11:       4667       4585   IO-APIC-level  BusLogic BT-958
 11:       4667       4585   IO-APIC-level  BusLogic BT-958
 11:       4667       4585   IO-APIC-level  BusLogic BT-958
 11:       4667       4585   IO-APIC-level  BusLogic BT-958
 11:       4670       4588   IO-APIC-level  BusLogic BT-958
 11:       4670       4588   IO-APIC-level  BusLogic BT-958
 11:       4670       4588   IO-APIC-level  BusLogic BT-958
 11:       4670       4588   IO-APIC-level  BusLogic BT-958
 11:       4670       4588   IO-APIC-level  BusLogic BT-958
 11:       4670       4588   IO-APIC-level  BusLogic BT-958
 11:       4670       4588   IO-APIC-level  BusLogic BT-958
 11:       4670       4588   IO-APIC-level  BusLogic BT-958

Cheers,
Dick Johnson
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