[ECOS] Execution time

Nick Garnett nickg@ecoscentric.com
Wed Sep 20 16:42:00 GMT 2006

Michele Portolan <micheleportolan@yahoo.it> writes:

> I would need to check the execution time of different implementations
> of the same function: is there a simple way to do it?
> I lloked up "tm_basic.cxx", but I think my case is far simpler because
> I have no scheduler (for the moment).
> Thanks anyone,

tm_basic shows the standard way of doing this: execute the test
routine many times in a loop, time the whole thing, and calculate the
time per run: total_time/loop_count .

Timing a single excecution is prone to all sorts of interference from
interrupts, cache effects, pipeline effects, DRAM refresh
etc. Multiple runs helps to minimize the effect of these things.

Nick Garnett                                 eCos Kernel Architect
http://www.ecoscentric.com            The eCos and RedBoot experts

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