Disable watchdog

Jan Kiszka jan.kiszka at siemens.com
Mon Feb 18 13:34:49 CET 2019


On 18.02.19 12:23, Giulio Moro via Xenomai wrote:
> Hi there,
> I have my kernel (4.4.113-ti-xenomai-r149 on BeagleBone BlacK) compiled with
> CONFIG_XENO_OPT_WATCHDOG=y
> CONFIG_XENO_OPT_WATCHDOG_TIMEOUT=4
> 
> I would like to experience the breeze of running without watchdog, to see what the bare-metal performance of the board are, removing the overhead of context switching and thread scheduling. I know this could be harmful for Linux, but I'd like to see what happens there. Is there any way I could disable the watchdog and have a thread busy waiting on a hardware flag, without recompiling the kernel with CONFIG_XENO_OPT_WATCHDOG=0 ?
> 
> I have tried  catching SIGXCPU, and also using pthread_sigmask, e.g.:
>          sigset_t set;
>          int s;
>          sigemptyset(&set);
>          sigaddset(&set, SIGXCPU);
>          s = pthread_sigmask(SIG_BLOCK, &set, NULL);
> 
> but in both cases my thread is temporarily preempted when the watchdog triggers.
> 

There is the module parameter "watchdog_timeout" which you cannot set to 0 but 
to very large number, even during runtime:

echo 999999 > /sys/module/xenomai/parameters/watchdog_timeout

Jan

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Corporate Competence Center Embedded Linux



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