lib: Add GPU power measurement

Read the RAPL power metrics courtesy of perf. Or your local HW
equivalent?

v2: uselocale()
v3: Use gpu_power_s(), gpu_power_J(), gpu_power_W() to try and make the
scale factors self-consistent.
v4: Use igt_sysfs
v5: s/tN/sampleN/

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>

1 files changed, 66 insertions, 0 deletions

diff --git a/lib/igt_gpu_power.h b/lib/igt_gpu_power.h
new file mode 100644
index 00000000..a578a02a0
--- /dev/null
+++ b/lib/igt_gpu_power.h
@@ -0,0 +1,66 @@
+/*
+ * Copyright © 2019 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ *
+ */
+
+#ifndef IGT_GPU_POWER_H
+#define IGT_GPU_POWER_H
+
+#include <stdbool.h>
+#include <stdint.h>
+
+struct gpu_power {
+	int fd;
+	double scale;
+};
+
+struct gpu_power_sample {
+	uint64_t energy;
+	uint64_t time;
+};
+
+int gpu_power_open(struct gpu_power *power);
+bool gpu_power_read(struct gpu_power *power, struct gpu_power_sample *s);
+void gpu_power_close(struct gpu_power *power);
+
+static inline double gpu_power_J(const struct gpu_power *p,
+				 const struct gpu_power_sample *p0,
+				 const struct gpu_power_sample *p1)
+{
+	return (p1->energy - p0->energy) * p->scale;
+}
+
+static inline double gpu_power_s(const struct gpu_power *p,
+				 const struct gpu_power_sample *p0,
+				 const struct gpu_power_sample *p1)
+{
+	return (p1->time - p0->time) * 1e-9;
+}
+
+static inline double gpu_power_W(const struct gpu_power *p,
+				 const struct gpu_power_sample *p0,
+				 const struct gpu_power_sample *p1)
+{
+	return gpu_power_J(p, p0, p1) / gpu_power_s(p, p0, p1);
+}
+
+#endif /* IGT_GPU_POWER_H */