[Rpcemu] 0.8.10/5.20: MIPS readout oddity

George george.greenfield at tiscali.co.uk
Wed Aug 21 09:04:09 PDT 2013


In message <20130821142519.GB31223 at spod.org>
          Peter Howkins <rpcemu.howkins at marutan.net> wrote:

> On Tue, Aug 20, 2013 at 05:09:40PM +0100, George wrote:
>> I've been running 0.8.10/5.20 daily for about a week now, and have
>> noticed an oddity relating to the MIPS readout on the header bar,
>> which seems to display activity (sometimes /a lot/ of activity - up to
>> 1400 on one occasion(!) and generally around 250-350 on my system*)
>> regardless of whether any application is active (i.e., when TaskUsage
>> will be displaying '0' or low single-figure activity levels).
> 
> RISC OS machine by default don't have any power-saving (with reduce
> cpu-usage off), they run flat out providing wimp null events even when
> there's no apps running anything. This busy-wait loop uses up CPU cycles,
> which are the MIPS you're seeing.
> 
[snip]
> 
>> Selecting Settings-Reduce CPU Usage doesn't
>> seem to affect the behaviour.
> 
> However, this should have kicked in the power-saving stuff. *provided*
> that the OS starts seeing enough null events, e.g. if you're running a
> task that uses all spare cpu in risc os, this will have no effect.
> 
> After about 10 seconds you should see the mips count start to drop ...
> unless something has changed in RO 5.20 from earlier ...

I re-selected Settings-Reduce CPU Usage this morning and hey presto, 
behaviour is back to normal, i.e., MIPS readout drops to 1 or 2 
shortly after desktop or other activity ceases. Hey ho.....

George

-- 
George



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