lib: Generalise rapl interface

We can use our existing rapl interface that monitors gpu power, to also
sample the other rapl domains such as package, cores and ram.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Andi Shyti <andi.shyti@intel.com>
Reviewed-by: Andi Shyti <andi.shyti@intel.com>

1 files changed, 69 insertions, 0 deletions

diff --git a/lib/igt_rapl.c b/lib/igt_rapl.c
new file mode 100644
index 00000000..03e49226
--- /dev/null
+++ b/lib/igt_rapl.c
@@ -0,0 +1,69 @@
+#include <ctype.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <locale.h>
+#include <math.h>
+#include <unistd.h>
+#include <inttypes.h>
+
+#include "igt_perf.h"
+#include "igt_rapl.h"
+#include "igt_sysfs.h"
+
+static int rapl_parse(struct rapl *r, const char *str)
+{
+	locale_t locale, oldlocale;
+	bool result = true;
+	char buf[128];
+	int dir;
+
+	memset(r, 0, sizeof(*r));
+
+	dir = open("/sys/devices/power", O_RDONLY);
+	if (dir < 0)
+		return -errno;
+
+	/* Replace user environment with plain C to match kernel format */
+	locale = newlocale(LC_ALL, "C", 0);
+	oldlocale = uselocale(locale);
+
+	result &= igt_sysfs_scanf(dir, "type", "%"PRIu64, &r->type) == 1;
+
+	snprintf(buf, sizeof(buf), "events/energy-%s", str);
+	result &= igt_sysfs_scanf(dir, buf, "event=%"PRIx64, &r->power) == 1;
+
+	snprintf(buf, sizeof(buf), "events/energy-%s.scale", str);
+	result &= igt_sysfs_scanf(dir, buf, "%lf", &r->scale) == 1;
+
+	uselocale(oldlocale);
+	freelocale(locale);
+
+	close(dir);
+
+	if (!result)
+		return -EINVAL;
+
+	if (isnan(r->scale) || !r->scale)
+		return -ERANGE;
+
+	return 0;
+}
+
+int rapl_open(struct rapl *r, const char *domain)
+{
+	r->fd = rapl_parse(r, domain);
+	if (r->fd < 0)
+		goto err;
+
+	r->fd = igt_perf_open(r->type, r->power);
+	if (r->fd < 0) {
+		r->fd = -errno;
+		goto err;
+	}
+
+	return 0;
+
+err:
+	errno = 0;
+	return r->fd;
+}