[riot-devel] Compute the time elapsed when switching between two threads

Joakim Nohlgård joakim.nohlgard at eistec.se
Thu Nov 15 18:38:43 CET 2018


Would you be able to get the measurements you are looking for using this
approach instead?
The low priority thread is toggling a gpio pin in a tight loop. The other
thread toggles a different pin as soon as it is resumed. You would need
external equipment to get the time between the two, but it should give a
fairly accurate measurement for a single context switch.
/Joakim

Den tor 15 nov. 2018 17:49 skrev Julien Gomez <
julien.gomez at student.uclouvain.be>:

> Hi Gaëtan,
>
> Thank you for your answer!
>
> I did look at this test and it counts the number of context switches
> between two threads of the same priority in one second.
>
> What I want is something more abstract (any thread, any priority). To
> reformulate my question, let's assume I have two threads. It doesn't matter
> what they are doing. One of the threads will be interrupted by the other
> and a context switch will occur. *What I want to know is how much time is
> spent in the context switching.*
>
> I don't think this is possible at the application-level.
>
> Regards,
> Julien
> ------------------------------
> *De :* Gaëtan Harter <gaetan.harter at fu-berlin.de>
> *Envoyé :* jeudi 15 novembre 2018 17:28:16
> *À :* devel at riot-os.org; Julien Gomez
> *Objet :* Re: [riot-devel] Compute the time elapsed when switching
> between two threads
>
> Hi Julien,
>
> I think this test should be doing what you want, I did not look at it
> just knew it existed.
>
>
>
> https://github.com/RIOT-OS/RIOT/tree/master/test/bench_thread_yield_pingpong
>
>
>
> Regards,
> Gaëtan - cladmi
>
> On 15.11.18 16:41, Julien Gomez wrote:
> > Hello fellow developers !
> >
> > I have a simple question: How one could compute the time elapsed when
> switching from thread A to thread B?
> >
> > Any advice or lead is welcome!
> >
> > Regards,
> > Julien
> >
> >
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> > devel at riot-os.org
> > https://lists.riot-os.org/mailman/listinfo/devel
> >
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