Introduce intel-gpu-overlay

A realtime display of GPU activity. Note, this is just at the point of
minimum usability...

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

1 files changed, 135 insertions, 0 deletions

diff --git a/overlay/chart.c b/overlay/chart.c
new file mode 100644
index 00000000..89b3f414
--- /dev/null
+++ b/overlay/chart.c
@@ -0,0 +1,135 @@
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <cairo.h>
+
+#include <stdio.h>
+
+#include "chart.h"
+
+int chart_init(struct chart *chart, const char *name, int num_samples)
+{
+	memset(chart, 0, sizeof(*chart));
+	chart->name = name;
+	chart->samples = malloc(sizeof(*chart->samples)*num_samples);
+	if (chart->samples == NULL)
+		return ENOMEM;
+
+	chart->num_samples = num_samples;
+	chart->range_automatic = 1;
+	return 0;
+}
+
+void chart_set_rgba(struct chart *chart, float red, float green, float blue, float alpha)
+{
+	chart->rgb[0] = red;
+	chart->rgb[1] = green;
+	chart->rgb[2] = blue;
+	chart->rgb[3] = alpha;
+}
+
+void chart_set_position(struct chart *chart, int x, int y)
+{
+	chart->x = x;
+	chart->y = y;
+}
+
+void chart_set_size(struct chart *chart, int w, int h)
+{
+	chart->w = w;
+	chart->h = h;
+}
+
+void chart_set_range(struct chart *chart, double min, double max)
+{
+	chart->range[0] = min;
+	chart->range[1] = max;
+	chart->range_automatic = 0;
+}
+
+void chart_add_sample(struct chart *chart, double value)
+{
+	int pos;
+
+	pos = chart->current_sample % chart->num_samples;
+	chart->samples[pos] = value;
+	chart->current_sample++;
+}
+
+static void chart_update_range(struct chart *chart)
+{
+	int n, max = chart->current_sample;
+	if (max > chart->num_samples)
+		max = chart->num_samples;
+	chart->range[0] = chart->range[1] = chart->samples[0];
+	for (n = 1; n < max; n++) {
+		if (chart->samples[n] < chart->range[0])
+			chart->range[0] = chart->samples[n];
+		else if (chart->samples[n] > chart->range[1])
+			chart->range[1] = chart->samples[n];
+	}
+}
+
+static double value_at(struct chart *chart, int n)
+{
+	if (n <= chart->current_sample - chart->num_samples)
+		n = chart->current_sample;
+	else if (n >= chart->current_sample)
+		n = chart->current_sample - 1;
+
+	return chart->samples[n % chart->num_samples];
+}
+
+static double gradient_at(struct chart *chart, int n)
+{
+	double y0, y1;
+
+	y0 = value_at(chart, n-1);
+	y1 = value_at(chart, n+1);
+
+	return (y1 - y0) / 2.;
+}
+
+void chart_draw(struct chart *chart, cairo_t *cr)
+{
+	int i, n, max, x;
+
+	if (chart->current_sample == 0)
+		return;
+
+	if (chart->range_automatic)
+		chart_update_range(chart);
+
+	cairo_save(cr);
+
+	cairo_translate(cr, chart->x, chart->y + chart->h);
+	cairo_scale(cr,
+		    chart->w / (double)chart->num_samples,
+		    -chart->h / (chart->range[1] - chart->range[0]));
+
+	x = 0;
+	max = chart->current_sample;
+	if (max >= chart->num_samples) {
+		max = chart->num_samples;
+		i = chart->current_sample - max;
+	} else {
+		i = 0;
+		x = chart->num_samples - max;
+	}
+	cairo_translate(cr, x, -chart->range[0]);
+
+	cairo_new_path(cr);
+	for (n = 0; n < max; n++) {
+		cairo_curve_to(cr,
+			       n-2/3., value_at(chart, i + n -1) + gradient_at(chart, i + n - 1)/3.,
+			       n-1/3., value_at(chart, i + n) - gradient_at(chart, i + n)/3.,
+			       n, value_at(chart, i + n));
+	}
+
+	cairo_identity_matrix(cr);
+	cairo_set_line_width(cr, 1);
+	cairo_set_source_rgba(cr, chart->rgb[0], chart->rgb[1], chart->rgb[2], chart->rgb[3]);
+	cairo_stroke(cr);
+
+	cairo_restore(cr);
+}