[Vm-dev] idle VM runs at constant 3-5% CPU load

Eliot Miranda eliot.miranda at gmail.com
Mon Jun 4 23:27:34 UTC 2012


On Mon, Jun 4, 2012 at 12:56 PM, Igor Stasenko <siguctua at gmail.com> wrote:

>
> i just wonder, what takes so much CPU time, even if it completely idle...
>

The basic issue is the idle process that spins doing a yield instead of
blocking.  Basically, instead of ioRelinquishProcessorForMicroseconds the
VM should enter a blocking call that will terminate when the next delay or
i/o event occurs.  This requires rearchitecting delays because currently
the VM polls for delay expiry.  For the VM to block while a delay is active
there must be a delay callback/signal/interrupt etc that has the
side-effect of terminating the blocking call.


>
>
> 4831-  NBCog        4.8
> 51519- NBCog        3.5
>
> if i kill a UI process, the load goes down to 2.5-3 % ...
> still too much.
>
> i would like to know how we can minimize this.
> The reason why i concerned is straightly pragmatic: extending battery
> life..
>
> i found that if i run completely on battery.. it depleting quite fast
> with VM running (and i don't do anything just coding, i.e not running
> benchmarks, but more thinking and typing).
>
> --
> Best regards,
> Igor Stasenko.
>



-- 
best,
Eliot
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