[perf] Move the calibration to its own function

Improve code clarity and whatnot.

1 files changed, 41 insertions, 30 deletions

diff --git a/perf/cairo-perf.c b/perf/cairo-perf.c
index b3afcd47..f2699feb 100644
--- a/perf/cairo-perf.c
+++ b/perf/cairo-perf.c
@@ -180,6 +180,42 @@ cairo_perf_can_run (cairo_perf_t	*perf,
     return FALSE;
 }
 
+static unsigned
+cairo_perf_calibrate (cairo_perf_t *perf,
+		      cairo_perf_func_t	 perf_func)
+{
+    cairo_perf_ticks_t calibration0, calibration;
+    unsigned loops, min_loops;
+
+    calibration0 = perf_func (perf->cr, perf->size, perf->size, 1);
+    if (perf->fast_and_sloppy) {
+	calibration = calibration0;
+    } else {
+	loops = cairo_perf_ticks_per_second () / 100 / calibration0;
+	if (loops < 3)
+	    loops = 3;
+	calibration = (calibration0 + perf_func (perf->cr, perf->size, perf->size, loops)) / (loops + 1);
+    }
+
+    /* XXX
+     * Compute the number of loops required for the timing
+     * interval to be perf->ms_per_iteration milliseconds. This
+     * helps to eliminate sampling variance due to timing and
+     * other systematic errors.  However, it also hides
+     * synchronisation overhead as we attempt to process a large
+     * batch of identical operations in a single shot. This can be
+     * considered both good and bad... It would be good to perform
+     * a more rigorous analysis of the synchronisation overhead,
+     * that is to estimate the time for loop=0.
+     */
+    loops = perf->ms_per_iteration * 0.001 * cairo_perf_ticks_per_second () / calibration;
+    min_loops = perf->fast_and_sloppy ? 1 : 10;
+    if (loops < min_loops)
+	loops = min_loops;
+
+    return loops;
+}
+
 void
 cairo_perf_run (cairo_perf_t		*perf,
 		const char		*name,
@@ -234,7 +270,6 @@ cairo_perf_run (cairo_perf_t		*perf,
 
     has_similar = cairo_perf_has_similar (perf);
     for (similar = 0; similar <= has_similar; similar++) {
-	cairo_perf_ticks_t calibration0, calibration;
 	unsigned loops;
 
 	if (perf->summary) {
@@ -252,32 +287,9 @@ cairo_perf_run (cairo_perf_t		*perf,
 	    cairo_push_group_with_content (perf->cr,
 		                           cairo_boilerplate_content (perf->target->content));
 	perf_func (perf->cr, perf->size, perf->size, 1);
-	calibration0 = perf_func (perf->cr, perf->size, perf->size, 1);
-	if (perf->fast_and_sloppy) {
-	    calibration = calibration0;
-	} else {
-	    loops = cairo_perf_ticks_per_second () / 100 / calibration0;
-	    if (loops < 3)
-		loops = 3;
-	    calibration = (calibration0 + perf_func (perf->cr, perf->size, perf->size, loops)) / (loops + 1);
-	    if (similar)
-		cairo_pattern_destroy (cairo_pop_group (perf->cr));
-	}
-
-	/* XXX
-	 * Compute the number of loops required for the timing
-	 * interval to be perf->ms_per_iteration milliseconds. This
-	 * helps to eliminate sampling variance due to timing and
-	 * other systematic errors.  However, it also hides
-	 * synchronisation overhead as we attempt to process a large
-	 * batch of identical operations in a single shot. This can be
-	 * considered both good and bad... It would be good to perform
-	 * a more rigorous analysis of the synchronisation overhead,
-	 * that is to estimate the time for loop=0.
-	 */
-	loops = perf->ms_per_iteration * 0.001 * cairo_perf_ticks_per_second () / calibration;
-	if (loops < 10)
-	    loops = perf->fast_and_sloppy ? 1 : 10;
+	loops = cairo_perf_calibrate (perf, perf_func);
+	if (similar)
+	    cairo_pattern_destroy (cairo_pop_group (perf->cr));
 
 	low_std_dev_count = 0;
 	for (i =0; i < perf->iterations; i++) {
@@ -319,12 +331,11 @@ cairo_perf_run (cairo_perf_t		*perf,
 	if (perf->summary) {
 	    _cairo_stats_compute (&stats, times, i);
 	    fprintf (perf->summary,
-		     "%10lld %#8.3f %#8.3f %#5.2f%% %3d %10lld\n",
+		     "%10lld %#8.3f %#8.3f %#5.2f%% %3d\n",
 		     (long long) stats.min_ticks,
 		     (stats.min_ticks * 1000.0) / cairo_perf_ticks_per_second (),
 		     (stats.median_ticks * 1000.0) / cairo_perf_ticks_per_second (),
-		     stats.std_dev * 100.0, stats.iterations,
-		     (long long) (calibration0 - stats.min_ticks));
+		     stats.std_dev * 100.0, stats.iterations);
 	    fflush (perf->summary);
 	}