Re: [PATCH] pip_stress: increase usleep for ARM devices

[Jorge Ramirez-Ortiz <jorge.ramirez-ortiz@linaro.org>]

On 12/10/2014 03:25 AM, chase.qi@linaro.org wrote:
> From: Chase Qi <chase.qi@linaro.org>
>
> Hello,
>
> pip_stress works out of the box on my x86 based laptop, but
> doesn't work on ARM devices, returned 'no inversion incurred'.
> Follow the comment to increase usleep value, 2500 worked for
> pandaboard and 3000 worked for Beaglebone Black board.
>
> I propose that increase the usleep value to 3500 from upstream,
> so that we can use pip_stress right out of the box.
>
> Please let me know if this is acceptable.

I think they should have modified main() to accept the lock time as a parameter
instead of simply adding some instructions in the comments

 * to show that it works. If you are having difficulty triggering an inversion,
 * merely increase the time that the low priority process sleeps while
 * holding the lock. (usleep);
 * Also note that you have to run as a user with permission to change
 * scheduling priorities.
 */

what I would do is actually
1. modify main to accept lock_time
2. send the patch to the rt-tests team




>
> Regards,
> Chase
>
> Signed-off-by: Chase Qi <chase.qi@linaro.org>
> ---
>  src/pi_tests/pip_stress.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/src/pi_tests/pip_stress.c b/src/pi_tests/pip_stress.c
> index 2b42b8f..553290b 100644
> --- a/src/pi_tests/pip_stress.c
> +++ b/src/pi_tests/pip_stress.c
> @@ -162,7 +162,7 @@ void low(pid_t pid)
>  				statep->inversion = 0;
>  			}
>  		Pthread_mutex_unlock(statep->mutex);
> -		usleep(500);
> +		usleep(3500);
>  	Pthread_mutex_unlock(resource);
>  	waitpid(pid, &status, 0);
>  }