Re: [LTP] [PATCH 11/11] [Realtime] sched_latency - Remove 'period missed' check dependency on thread starting time

[Subrata M. <su...@li...>]

The Final one also Merged.

Thanks--
Subrata

On Thu, 2008-02-14 at 13:37 +0100, Sebastien Dugue wrote:
>   The 'period missed' check of the thread first loop should not depend on the
> thread starting time. This is especially visible on 'slow' platforms where
> one cannot run the test if thread creation takes a long time.
> 
>  Fix it by removing this dependency. All delays are now calculated relative
> to when the thread starts.
> 
> Signed-off-by: Sebastien Dugue <seb...@bu...>
> Cc: Darren Hart <dv...@us...>
> Cc: Tim Chavez <ti...@us...>
> Cc: Matthieu CASTET <mat...@pa...>
> ---
>  .../realtime/func/sched_latency/sched_latency.c    |   13 ++++++-------
>  1 files changed, 6 insertions(+), 7 deletions(-)
> 
> diff --git a/testcases/realtime/func/sched_latency/sched_latency.c b/testcases/realtime/func/sched_latency/sched_latency.c
> index b7ba74b..8500525 100644
> --- a/testcases/realtime/func/sched_latency/sched_latency.c
> +++ b/testcases/realtime/func/sched_latency/sched_latency.c
> @@ -121,12 +121,11 @@ void *periodic_thread(void *arg)
>  	int i;
>  	nsec_t delay, avg_delay = 0, start_delay, min_delay = -1ULL, max_delay = 0;
>  	int failures = 0;
> -	nsec_t next = 0, now = 0, sched_delta = 0, delta = 0, prev = 0;
> +	nsec_t next = 0, now = 0, sched_delta = 0, delta = 0, prev = 0, iter_start;
> 
> -	prev = start;
> -	next = start;
>  	now = rt_gettime();
>  	start_delay = (now - start)/NS_PER_US;
> +	iter_start = next = now;
> 
>  	debug(DBG_INFO, "ITERATION DELAY(US) MAX_DELAY(US) FAILURES\n");
>  	debug(DBG_INFO, "--------- --------- ------------- --------\n");
> @@ -147,9 +146,9 @@ void *periodic_thread(void *arg)
>  			printf("        actual delta: %8llu us\n", delta/1000);
>  			printf("             latency: %8llu us\n", (delta-sched_delta)/1000);
>  			printf("---------------------------------------\n");
> -			printf("      previous start: %8llu us\n", (prev-start)/1000);
> -			printf("                 now: %8llu us\n", (now-start)/1000);
> -			printf("     scheduled start: %8llu us\n", (next-start)/1000);
> +			printf("      previous start: %8llu us\n", (prev-iter_start)/1000);
> +			printf("                 now: %8llu us\n", (now-iter_start)/1000);
> +			printf("     scheduled start: %8llu us\n", (next-iter_start)/1000);
>  			printf("next scheduled start is in the past!\n");
>  			ret = 1;
>  			break;
> @@ -167,7 +166,7 @@ void *periodic_thread(void *arg)
>  		} while (now < next);
> 
>  		/* start of period */
> -		delay = (now - start - (nsec_t)(i+1)*period)/NS_PER_US;
> +		delay = (now - iter_start - (nsec_t)(i+1)*period)/NS_PER_US;
>  		dat.records[i].x = i;
>  		dat.records[i].y = delay;
>  		if (delay < min_delay)