From 4654968d3a7da18d6ed97e9c836b1dadb01e78a9 Mon Sep 17 00:00:00 2001
From: "Peter W. Draper" <p.w.draper@durham.ac.uk>
Date: Wed, 2 Mar 2016 15:11:29 +0000
Subject: [PATCH] Use clock_gettime() to time steps
Simplest possible version. Still reports tick value for comparison.
---
src/engine.c | 37 ++++++++++++++++++++++++++++++++++---
src/engine.h | 1 +
2 files changed, 35 insertions(+), 3 deletions(-)
diff --git a/src/engine.c b/src/engine.c
index 272d5c0c9f..d842f4835c 100644
--- a/src/engine.c
+++ b/src/engine.c
@@ -28,6 +28,7 @@
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
+#include <time.h>
#include <unistd.h>
#include <stdbool.h>
@@ -1464,6 +1465,29 @@ void engine_init_particles(struct engine *e) {
e->step = -1;
}
+
+/**
+ * brief Get difference in milli-seconds between two timespecs.
+ *
+ * @param start the start time.
+ * @param end the end time.
+ *
+ * @return the difference in milli-secinds.
+ */
+static double time_diff(struct timespec start, struct timespec end)
+{
+ struct timespec temp;
+ if ((end.tv_nsec-start.tv_nsec)<0) {
+ temp.tv_sec = end.tv_sec-start.tv_sec-1;
+ temp.tv_nsec = 1000000000+end.tv_nsec-start.tv_nsec;
+ } else {
+ temp.tv_sec = end.tv_sec-start.tv_sec;
+ temp.tv_nsec = end.tv_nsec-start.tv_nsec;
+ }
+ return (double)temp.tv_sec*1000.0 + (double)temp.tv_nsec*1.0E-6;
+}
+
+
/**
* @brief Let the #engine loose to compute the forces.
*
@@ -1482,6 +1506,9 @@ void engine_step(struct engine *e) {
TIMER_TIC2;
+ struct timespec time1, time2;
+ clock_gettime(CLOCK_REALTIME, &time1);
+
/* Collect the cell data. */
for (k = 0; k < s->nr_cells; k++)
if (s->cells[k].nodeID == e->nodeID) {
@@ -1553,8 +1580,8 @@ void engine_step(struct engine *e) {
if (e->nodeID == 0) {
/* Print some information to the screen */
- printf("%d %e %e %d %.3f\n", e->step, e->time, e->timeStep, updates,
- e->wallclock_time);
+ printf("%d %e %e %d %.3f %.3f\n", e->step, e->time, e->timeStep, updates,
+ e->wallclock_time, e->wallclock_time_ticks);
fflush(stdout);
/* Write some energy statistics */
@@ -1620,7 +1647,11 @@ void engine_step(struct engine *e) {
TIMER_TOC2(timer_step);
- e->wallclock_time = ((double)timers[timer_count - 1]) / CPU_TPS * 1000;
+ clock_gettime(CLOCK_REALTIME, &time2);
+
+ e->wallclock_time_ticks = ((double)timers[timer_count - 1]) / CPU_TPS * 1000;
+
+ e->wallclock_time = (float) time_diff(time1, time2);
// printParticle(e->s->parts, e->s->xparts,1000, e->s->nr_parts);
// printParticle(e->s->parts, e->s->xparts,515050, e->s->nr_parts);
}
diff --git a/src/engine.h b/src/engine.h
index 13c7ec4061..bba53092e2 100644
--- a/src/engine.h
+++ b/src/engine.h
@@ -147,6 +147,7 @@ struct engine {
/* Wallclock time of the last time-step */
float wallclock_time;
+ float wallclock_time_ticks;
/* Force the engine to rebuild? */
int forcerebuild;
--
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