Make the traditional speedup vs. slowdown report style available again

Now, if you pass exactly two performance reports on the command line
you'll get the traditional report style again, (so the tool remains
backwards compatible). If you really want the new style with two
reports you can get it by adding /dev/null as a third argument.

1 files changed, 103 insertions, 9 deletions

diff --git a/perf/cairo-perf-diff-files.c b/perf/cairo-perf-diff-files.c
index 2bad7d988..d534fb7d6 100644
--- a/perf/cairo-perf-diff-files.c
+++ b/perf/cairo-perf-diff-files.c
@@ -444,6 +444,29 @@ cairo_perf_report_load (cairo_perf_report_t *report, const char *filename)
 }
 
 static int
+test_diff_cmp_speedup_before_slowdown (const void *a, const void *b)
+{
+    const test_diff_t *a_diff = a;
+    const test_diff_t *b_diff = b;
+
+    /* First make all speedups come before all slowdowns. */
+    if (a_diff->change > 1.0 && b_diff->change < 1.0)
+	return -1;
+    if (a_diff->change < 1.0 && b_diff->change > 1.0)
+	return 1;
+
+    /* Reverse sort by magnitude of change so larger changes come
+     * first */
+    if (fabs (a_diff->change) > fabs (b_diff->change))
+	return -1;
+
+    if (fabs (a_diff->change) < fabs (b_diff->change))
+	return 1;
+
+    return 0;
+}
+
+static int
 test_diff_cmp (const void *a, const void *b)
 {
     const test_diff_t *a_diff = a;
@@ -507,9 +530,33 @@ print_change_bar (double change, double max_change, int use_utf)
 }
 
 static void
-test_diff_print (test_diff_t			*diff,
-		 double				 max_change,
-		 cairo_perf_report_options_t	*options)
+test_diff_print_binary (test_diff_t			*diff,
+			double				 max_change,
+			cairo_perf_report_options_t	*options)
+{
+    printf ("%5s-%-4s %26s-%-3d  %6.2f %4.2f%% -> %6.2f %4.2f%%: %5.2fx ",
+	    diff->tests[0]->backend, diff->tests[0]->content,
+	    diff->tests[0]->name, diff->tests[0]->size,
+	    diff->tests[0]->stats.median_ticks / diff->tests[0]->stats.ticks_per_ms,
+	    diff->tests[0]->stats.std_dev * 100,
+	    diff->tests[1]->stats.median_ticks / diff->tests[1]->stats.ticks_per_ms,
+	    diff->tests[1]->stats.std_dev * 100,
+	    fabs (diff->change));
+
+    if (diff->change > 1.0)
+	printf ("speedup\n");
+    else
+	printf ("slowdown\n");
+
+    if (options->print_change_bars)
+	print_change_bar (fabs (diff->change), max_change,
+			  options->use_utf);
+}
+
+static void
+test_diff_print_multi (test_diff_t			*diff,
+		       double				 max_change,
+		       cairo_perf_report_options_t	*options)
 {
     int i;
     double test_time;
@@ -551,6 +598,8 @@ cairo_perf_reports_compare (cairo_perf_report_t		*reports,
     double max_change;
     double test_time;
     cairo_bool_t seen_non_null;
+    cairo_bool_t printed_speedup = FALSE;
+    cairo_bool_t printed_slowdown = FALSE;
 
     assert (num_reports >= 2);
 
@@ -613,16 +662,41 @@ cairo_perf_reports_compare (cairo_perf_report_t		*reports,
 	}
 	diff->change = diff->max / diff->min;
 
+	if (num_reports == 2) {
+	    double old_time, new_time;
+	    if (diff->num_tests == 1) {
+		printf ("Only in %s: %s %s\n",
+			diff->tests[0]->configuration,
+			diff->tests[0]->backend,
+			diff->tests[0]->name);
+		continue;
+	    }
+	    old_time = diff->tests[0]->stats.min_ticks;
+	    new_time = diff->tests[1]->stats.min_ticks;
+	    if (options->use_ms) {
+		old_time /= diff->tests[0]->stats.ticks_per_ms;
+		new_time /= diff->tests[1]->stats.ticks_per_ms;
+	    }
+	    diff->change = old_time / new_time;
+	    if (diff->change < 1.0)
+		diff->change = - 1.0 / diff->change;
+	}
+
 	diff++;
 	num_diffs++;
     }
 
-    qsort (diffs, num_diffs, sizeof (test_diff_t), test_diff_cmp);
+    if (num_reports == 2)
+	qsort (diffs, num_diffs, sizeof (test_diff_t),
+	       test_diff_cmp_speedup_before_slowdown);
+    else
+	qsort (diffs, num_diffs, sizeof (test_diff_t), test_diff_cmp);
 
     max_change = 1.0;
-    for (i = 0; i < num_diffs; i++)
-	if (diffs[i].change > max_change)
-	    max_change = diffs[i].change;
+    for (i = 0; i < num_diffs; i++) {
+	if (fabs (diffs[i].change) > max_change)
+	    max_change = fabs (diffs[i].change);
+    }
 
     for (i = 0; i < num_diffs; i++) {
 	diff = &diffs[i];
@@ -630,10 +704,30 @@ cairo_perf_reports_compare (cairo_perf_report_t		*reports,
 	/* Discard as uninteresting a change which is less than the
 	 * minimum change required, (default may be overriden on
 	 * command-line). */
-	if (diff->change - 1.0 < options->min_change)
+	if (fabs (diff->change) - 1.0 < options->min_change)
 	    continue;
 
-	test_diff_print (diff, max_change, options);
+	if (num_reports == 2) {
+	    if (i == 0) {
+		printf ("old: %s\n"
+			"new: %s\n",
+			diffs->tests[0]->configuration,
+			diffs->tests[1]->configuration);
+	    }
+	    if (diff->change > 1.0 && ! printed_speedup) {
+		printf ("Speedups\n"
+			"========\n");
+		printed_speedup = TRUE;
+	    }
+	    if (diff->change < 1.0 && ! printed_slowdown) {
+		printf ("Slowdowns\n"
+			"=========\n");
+		printed_slowdown = TRUE;
+	    }
+	    test_diff_print_binary (diff, max_change, options);
+	} else {
+	    test_diff_print_multi (diff, max_change, options);
+	}
     }
 
     for (i = 0; i < num_diffs; i++)