There was an error in previous patch. Please find attached corrected patch.
cheers,
Piotr
From 5610e2b01e5302a5ecff7ca368198863a6ce9f78 Mon Sep 17 00:00:00 2001
From: Piotr Gregor <piotrgregor@xxxxxxxxxxx>
Date: Fri, 11 Nov 2016 11:28:09 +0000
Subject: [PATCH] rt-tests: cyclictest: Calculate average latencies on the fly
Prevents stat->avg variable from overflow.
---
src/cyclictest/cyclictest.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/src/cyclictest/cyclictest.c b/src/cyclictest/cyclictest.c
index 3f1bef1..0d2ddbc 100644
--- a/src/cyclictest/cyclictest.c
+++ b/src/cyclictest/cyclictest.c
@@ -1178,7 +1178,11 @@ static void *timerthread(void *param)
if (refresh_on_max)
pthread_cond_signal(&refresh_on_max_cond);
}
- stat->avg += (double) diff;
+ if (stat->cycles == 0) {
+ stat->avg = (double) diff;
+ } else {
+ stat->avg = (stat->avg + (double) diff / (double) stat->cycles) * ((double) stat->cycles / (double) (stat->cycles + 1));
+ }
if (trigger && (diff > trigger)) {
trigger_update(par, diff, calctime(now));
@@ -2005,7 +2009,7 @@ static void print_hist(struct thread_param *par[], int nthreads)
fprintf(fd, "# Avg Latencies:");
for (j = 0; j < nthreads; j++)
fprintf(fd, " %05lu", par[j]->stats->cycles ?
- (long)(par[j]->stats->avg/par[j]->stats->cycles) : 0);
+ (long)(par[j]->stats->avg) : 0);
fprintf(fd, "\n");
fprintf(fd, "# Max Latencies:");
maxmax = 0;
@@ -2059,7 +2063,7 @@ static void print_stat(FILE *fp, struct thread_param *par, int index, int verbos
fprintf(fp, fmt, index, stat->tid, par->prio,
par->interval, stat->cycles, stat->min,
stat->act, stat->cycles ?
- (long)(stat->avg/stat->cycles) : 0, stat->max);
+ (long)(stat->avg) : 0, stat->max);
if (smi)
fprintf(fp," SMI:%8ld", stat->smi_count);
--
2.7.4
