On Monday 06 July 2009 21:20:49 Subrata Modak wrote:
> On Fri, 2009-07-03 at 12:35 +0530, Sripathi Kodi wrote:
> > Hi,
> >
> > The pass criterion in pi_perf test case is wrong. It compares the minimum
> > amount of time taken by the low priority thread with the maximum amount
> > of time taken by the high priority thread to calculate the PI delay.
> > Obviously, these min and max don't necessarily happen in the same
> > iteration, resulting in a number of false failures. The correct way is to
> > compare the time taken by low and high priority threads in each iteration
> > and then find the maximum delay experienced by high priority thread
> > across the iterations. This patch implements the change. Additionally,
> > this patch removes lock_wait_dat array, which is not needed anymore as
> > well as makes a couple of messages easier to understand.
> >
> > This patch changes the messages displayed by this test case slightly.
> > They look like the following now:
> >
> > Low prio thread started
> > High prio thread started
> > Busy 0 started
> > Busy 1 started
> > Busy 2 started
> > Busy 3 started
> > Time taken for high prio thread to get the lock once released by low prio
> > thread
> > Min delay = 10 us
> > Max delay = 36 us
> > Average delay = 17.06 us
> > Standard Deviation = 8.11 us
> > Quantiles:
> > 99.0% < 36
> > Criteria: High prio lock wait time < (Low prio lock held time + 200 us)
> > Result: PASS
> >
> > I have tested this by running 1000 iterations of pi_perf test on a couple
> > of machines.
> >
> > Thanks,
> > Sripathi.
> >
> > ---
> >
> > realtime: Fix the pass criterion of pi_perf test case.
> >
> > Signed-off-by: Sripathi Kodi <[email protected]>
>
> Hi Sri,
>
> Is this based on the latest snapshot. I get the following failures:
>
> patching file testcases/realtime/func/pi_perf/pi_perf.c
> Hunk #1 FAILED at 1.
>
>
> Can you please resend ?
Sorry Subrata, the patch seems to be fine on my machine, but is going bad in my
mail client. If you don't mind, I have attached the patch to this mail for
now.
Thanks,
Sripathi.
--
realtime: Fix the pass criterion of pi_perf test case.
Signed-off-by: Sripathi Kodi <[email protected]>
Acked-by: Will Schmidt <[email protected]>
Acked-by: Gowrishankar <[email protected]>
<snip>
diff -uprN ltp_cvs_3jul_org/testcases/realtime/func/pi_perf/pi_perf.c ltp_cvs_3jul/testcases/realtime/func/pi_perf/pi_perf.c
--- ltp_cvs_3jul_org/testcases/realtime/func/pi_perf/pi_perf.c 2009-07-03 12:21:41.000000000 +0530
+++ ltp_cvs_3jul/testcases/realtime/func/pi_perf/pi_perf.c 2009-07-03 12:24:44.000000000 +0530
@@ -1,6 +1,6 @@
/******************************************************************************
*
- * Copyright © International Business Machines Corp., 2007, 2008
+ * Copyright © International Business Machines Corp., 2007, 2008, 2009
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
@@ -36,6 +36,8 @@
*
* HISTORY
* 2007-Nov-20: Initial version by Sripathi Kodi <[email protected]>
+ * 2009-Jul-03: Pass criteria corrected by Sripathi Kodi
+ * <[email protected]>
*
*****************************************************************************/
@@ -71,9 +73,9 @@ static unsigned int high_work_time = DEF
static unsigned int busy_work_time;
static int num_busy = -1;
-nsec_t low_unlock, high_get_lock;
+nsec_t low_unlock, max_pi_delay;
-stats_container_t lock_wait_dat, low_dat, cpu_delay_dat;
+stats_container_t low_dat, cpu_delay_dat;
stats_container_t cpu_delay_hist;
stats_quantiles_t cpu_delay_quantiles;
@@ -165,10 +167,9 @@ void * low_prio_thread(void *arg)
void * high_prio_thread(void *arg)
{
- nsec_t high_start, high_spent, high_end;
+ nsec_t high_start, high_end, high_get_lock;
unsigned int i;
- stats_container_init(&lock_wait_dat, iterations);
stats_container_init(&cpu_delay_dat, iterations);
stats_container_init(&cpu_delay_hist, HIST_BUCKETS);
stats_quantiles_init(&cpu_delay_quantiles, (int)log10(iterations));
@@ -184,14 +185,11 @@ void * high_prio_thread(void *arg)
high_start = rt_gettime();
pthread_mutex_lock(&lock);
high_end = rt_gettime();
- high_spent = high_end - high_start;
high_get_lock = high_end - low_unlock;
busy_work_ms(high_work_time);
pthread_mutex_unlock(&lock);
- lock_wait_dat.records[i].x = i;
- lock_wait_dat.records[i].y = high_spent / NS_PER_US;
cpu_delay_dat.records[i].x = i;
cpu_delay_dat.records[i].y = high_get_lock / NS_PER_US;
@@ -206,14 +204,16 @@ void * high_prio_thread(void *arg)
"Latency (us)", "Samples", &cpu_delay_hist, "steps");
printf("Time taken for high prio thread to get the lock once released by low prio thread\n");
- printf("Min wait time = %ld us\n", stats_min(&cpu_delay_dat));
- printf("Max wait time = %ld us\n", stats_max(&cpu_delay_dat));
- printf("Average wait time = %4.2f us\n", stats_avg(&cpu_delay_dat));
+ printf("Min delay = %ld us\n", stats_min(&cpu_delay_dat));
+ printf("Max delay = %ld us\n", stats_max(&cpu_delay_dat));
+ printf("Average delay = %4.2f us\n", stats_avg(&cpu_delay_dat));
printf("Standard Deviation = %4.2f us\n", stats_stddev(&cpu_delay_dat));
printf("Quantiles:\n");
stats_quantiles_calc(&cpu_delay_dat, &cpu_delay_quantiles);
stats_quantiles_print(&cpu_delay_quantiles);
+ max_pi_delay = stats_max(&cpu_delay_dat);
+
return NULL;
}
@@ -261,13 +261,11 @@ int main(int argc, char *argv[])
}
join_threads();
- printf("Low prio lock held time (min) = %ld us\n", stats_min(&low_dat));
- printf("High prio lock wait time (max) = %ld us\n", stats_max(&lock_wait_dat));
printf("Criteria: High prio lock wait time < "
"(Low prio lock held time + %d us)\n", (int)pass_criteria);
ret = 0;
- if (stats_max(&lock_wait_dat) > stats_min(&low_dat) + (int)pass_criteria)
+ if (max_pi_delay > pass_criteria)
ret = 1;
printf("Result: %s\n", ret ? "FAIL" : "PASS");
------------------------------------------------------------------------------
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