[PATCH v3 2/5] latencystats: handle fractional cycles per ns

[Stephen Hemminger]

The timer_hz is not always an integral number of nanoseconds.
For examples, cycles per nanoseconds on my test system is 2.8.
Fix by using floating point where needed.

Signed-off-by: Stephen Hemminger <stephen at networkplumber.org>
---
 lib/latencystats/rte_latencystats.c | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/lib/latencystats/rte_latencystats.c b/lib/latencystats/rte_latencystats.c
index 9b345bfb33..fe8c3c563a 100644
--- a/lib/latencystats/rte_latencystats.c
+++ b/lib/latencystats/rte_latencystats.c
@@ -19,10 +19,10 @@
 #define NS_PER_SEC 1E9
 
 /** Clock cycles per nano second */
-static uint64_t
+static float
 latencystat_cycles_per_ns(void)
 {
-	return rte_get_timer_hz() / NS_PER_SEC;
+	return (double)rte_get_timer_hz() / NS_PER_SEC;
 }
 
 RTE_LOG_REGISTER_DEFAULT(latencystat_logtype, INFO);
@@ -89,8 +89,7 @@ rte_latencystats_update(void)
 	for (i = 0; i < NUM_LATENCY_STATS; i++) {
 		stats_ptr = RTE_PTR_ADD(glob_stats,
 				lat_stats_strings[i].offset);
-		values[i] = (uint64_t)floor((*stats_ptr)/
-				latencystat_cycles_per_ns());
+		values[i] = floor(*stats_ptr / latencystat_cycles_per_ns());
 	}
 
 	ret = rte_metrics_update_values(RTE_METRICS_GLOBAL,
@@ -112,8 +111,7 @@ rte_latencystats_fill_values(struct rte_metric_value *values)
 		stats_ptr = RTE_PTR_ADD(glob_stats,
 				lat_stats_strings[i].offset);
 		values[i].key = i;
-		values[i].value = (uint64_t)floor((*stats_ptr)/
-						latencystat_cycles_per_ns());
+		values[i].value = floor(*stats_ptr / latencystat_cycles_per_ns());
 	}
 }
 
@@ -237,7 +235,7 @@ rte_latencystats_init(uint64_t app_samp_intvl,
 
 	glob_stats = mz->addr;
 	rte_spinlock_init(&glob_stats->lock);
-	samp_intvl = app_samp_intvl * latencystat_cycles_per_ns();
+	samp_intvl = floor(app_samp_intvl * latencystat_cycles_per_ns());
 
 	/** Register latency stats with stats library */
 	for (i = 0; i < NUM_LATENCY_STATS; i++)
-- 
2.43.0