[MAGEEC] Energy cost of context switching

Kerstin Eder Kerstin.Eder at bristol.ac.uk
Tue Nov 19 18:51:21 GMT 2013

Hi Jeremy,

This would make an interesting student project - investigate polling vs 
interrupts for different platforms / loads.  ;)
It could start end Jan and we would have a comprehensive set of results 
by Sept.

Some indicative results would help at this stage to motivate the 
project, but clearly there are different opinions on this so it must be 
tested out.

Best wishes,

On 19/11/13 18:38, Jeremy Bennett wrote:
> Chris Shaw of ARM had a slide at the NMI meeting yesterday, in which he
> suggested you should always prefer interrupts over polling.
> I challenged this (as I often do), since it actually depends on your
> latency and throughput, but in many circumstances polling, or at least
> time-triggered polling is going to be better.
> The assumption I was making was that context switching uses a lot of
> energy. Chris Shaw is pushing back on this, particularly for the
> Cortex-M series, which have very efficient context switching.
> Do we have any data on this. If not how easy would it be to create some
> artificial loads and compare polling with switching in different scenarios?
> Jeremy

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