overlay: Add rc6 residency

Not much point at the moment since we use forcewake to continuously
probe the GPU busyness. But that will eventually change to a more
power-efficient in-kernel.

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

overlay/Makefile.am

@@ -25,6 +25,8 @@ intel_gpu_overlay_SOURCES = \
 	gpu-freq.c \
 	igfx.h \
 	igfx.c \
+	rc6.h \
+	rc6.c \
 	$(NULL)
 
 if BUILD_OVERLAY_XLIB

overlay/overlay.c

@@ -17,6 +17,7 @@
 #include "gpu-freq.h"
 #include "gpu-top.h"
 #include "gpu-perf.h"
+#include "rc6.h"
 
 const cairo_user_data_key_t overlay_key;
 
@@ -71,6 +72,7 @@ struct overlay_gpu_perf {
 
 struct overlay_gpu_freq {
 	struct gpu_freq gpu_freq;
+	struct rc6 rc6;
 	struct chart current;
 	struct chart request;
 	int error;
@@ -213,7 +215,7 @@ static char *get_comm(pid_t pid, char *comm, int len)
 
 	fd = open(filename, 0);
 	if (fd >= 0) {
-		len = read(fd, comm, len-1);
+		len = read(fd, comm, len);
 		if (len >= 0)
 			comm[len-1] = '\0';
 		close(fd);
@@ -389,6 +391,8 @@ static void init_gpu_freq(struct overlay_context *ctx,
 	if (gf->error)
 		return;
 
+	rc6_init(&gf->rc6);
+
 	chart_init(&gf->current, "current", 120);
 	chart_set_position(&gf->current, 12, ctx->height/2 + 6);
 	chart_set_size(&gf->current, ctx->width/2 - 18, ctx->height/2 - 18);
@@ -437,6 +441,18 @@ static void show_gpu_freq(struct overlay_context *ctx, struct overlay_gpu_freq *
 	cairo_move_to(ctx->cr, 12, y);
 	cairo_show_text(ctx->cr, buf);
 	y += 14;
+
+	if (rc6_update(&gf->rc6) == 0) {
+		sprintf(buf, "RC6: %d%%", gf->rc6.rc6_combined);
+		cairo_move_to(ctx->cr, 12, y);
+		cairo_show_text(ctx->cr, buf);
+		if (gf->rc6.rc6_combined) {
+			sprintf(buf, " [rc6=%d%%, rc6p=%d%%, rc6pp=%d%%]",
+				gf->rc6.rc6, gf->rc6.rc6p, gf->rc6.rc6pp);
+			cairo_show_text(ctx->cr, buf);
+		}
+		y += 14;
+	}
 }
 
 static void init_gem_objects(struct overlay_context *ctx,

overlay/rc6.c

@@ -0,0 +1,93 @@
+#include <sys/stat.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <time.h>
+#include <errno.h>
+
+#include "rc6.h"
+
+int rc6_init(struct rc6 *rc6)
+{
+	struct stat st;
+	int fd;
+
+	memset(rc6, 0, sizeof(*rc6));
+
+	fd = stat("/sys/class/drm/card0/power", &st);
+	if (fd == -1)
+		return rc6->error = errno;
+
+	return 0;
+}
+
+static uint64_t file_to_u64(const char *path)
+{
+	char buf[4096];
+	int fd, len;
+
+	fd = open(path, 0);
+	if (fd < 0)
+		return 0;
+
+	len = read(fd, buf, sizeof(buf)-1);
+	close(fd);
+
+	if (len < 0)
+		return 0;
+
+	buf[len] = '\0';
+
+	return strtoull(buf, 0, 0);
+}
+
+static uint64_t clock_ms_to_u64(void)
+{
+	struct timespec tv;
+
+	if (clock_gettime(CLOCK_MONOTONIC, &tv) < 0)
+		return 0;
+
+	return (uint64_t)tv.tv_sec * 1000 + tv.tv_nsec / 10000000;
+}
+
+int rc6_update(struct rc6 *rc6)
+{
+	struct rc6_stat *s = &rc6->stat[rc6->count++&1];
+	struct rc6_stat *d = &rc6->stat[rc6->count&1];
+	uint64_t d_time, d_rc6, d_rc6p, d_rc6pp;
+	struct stat st;
+
+	if (rc6->error)
+		return rc6->error;
+
+	if (stat("/sys/class/drm/card0/power", &st) < 0)
+		return rc6->error = errno;
+
+	if (stat("/sys/class/drm/card0/power/rc6_residency_ms", &st) < 0)
+		return ENOENT;
+
+	s->rc6_residency = file_to_u64("/sys/class/drm/card0/power/rc6_residency_ms");
+	s->rc6p_residency = file_to_u64("/sys/class/drm/card0/power/rc6p_residency_ms");
+	s->rc6pp_residency = file_to_u64("/sys/class/drm/card0/power/rc6pp_residency_ms");
+	s->timestamp = clock_ms_to_u64();
+
+	if (rc6->count == 1)
+		return EAGAIN;
+
+	d_time = s->timestamp - d->timestamp;
+
+	d_rc6 = s->rc6_residency - d->rc6_residency;
+	rc6->rc6 = 100 * d_rc6 / d_time;
+
+	d_rc6p = s->rc6p_residency - d->rc6p_residency;
+	rc6->rc6p = 100 * d_rc6p / d_time;
+
+	d_rc6pp = s->rc6pp_residency - d->rc6pp_residency;
+	rc6->rc6pp = 100 * d_rc6pp / d_time;
+
+	rc6->rc6_combined = 100 * (d_rc6 + d_rc6p + d_rc6pp) / d_time;
+	return 0;
+}

overlay/rc6.h

@@ -0,0 +1,21 @@
+#include <stdint.h>
+
+struct rc6 {
+	struct rc6_stat {
+		uint64_t rc6_residency;
+		uint64_t rc6p_residency;
+		uint64_t rc6pp_residency;
+		uint64_t timestamp;
+	} stat[2];
+
+	int count;
+	int error;
+
+	uint8_t rc6;
+	uint8_t rc6p;
+	uint8_t rc6pp;
+	uint8_t rc6_combined;
+};
+
+int rc6_init(struct rc6 *rc6);
+int rc6_update(struct rc6 *rc6);