Add helpers for getting RAPL power data from Intel CPUs

common/common-power.c

@@ -0,0 +1,165 @@
+/*
+
+Copyright (c) 2017-2019, Feral Interactive
+Copyright (c) 2019, Intel Corporation
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+ * Redistributions of source code must retain the above copyright notice,
+   this list of conditions and the following disclaimer.
+ * Redistributions in binary form must reproduce the above copyright
+   notice, this list of conditions and the following disclaimer in the
+   documentation and/or other materials provided with the distribution.
+ * Neither the name of Feral Interactive nor the names of its contributors
+   may be used to endorse or promote products derived from this software
+   without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGE.
+
+ */
+
+#define _GNU_SOURCE
+
+#include "common-power.h"
+#include "common-logging.h"
+
+#include <assert.h>
+#include <ctype.h>
+#include <glob.h>
+#include <linux/limits.h>
+#include <stdio.h>
+#include <string.h>
+
+static bool read_file_in_dir(const char *dir, const char *file, char *dest, size_t n)
+{
+	char path[PATH_MAX];
+	int ret = snprintf(path, sizeof(path), "%s/%s", dir, file);
+	if (ret < 0 || ret >= (int)sizeof(path)) {
+		LOG_ERROR("Path length overrun");
+		return false;
+	}
+
+	FILE *f = fopen(path, "r");
+	if (!f) {
+		LOG_ERROR("Failed to open file for read %s\n", path);
+		return false;
+	}
+
+	size_t read = fread(dest, 1, n, f);
+
+	/* Close before we do any error checking */
+	fclose(f);
+
+	if (read <= 0) {
+		LOG_ERROR("Failed to read contents of %s: (%s)\n", path, strerror(errno));
+		return false;
+	}
+
+	if (read >= n) {
+		LOG_ERROR("File contained more data than expected %s\n", path);
+		return false;
+	}
+
+	/* Ensure we're null terminated */
+	dest[read] = '\0';
+
+	/* Trim whitespace off the end */
+	while (read > 0 && isspace(dest[read - 1])) {
+		dest[read - 1] = '\0';
+		read--;
+	}
+
+	return true;
+}
+
+static bool get_energy_uj(const char *rapl_name, uint32_t *energy_uj)
+{
+	glob_t glo = { 0 };
+	static const char *path = "/sys/class/powercap/intel-rapl/intel-rapl:0/intel-rapl:0:*";
+
+	/* Assert some sanity on this glob */
+	if (glob(path, GLOB_NOSORT, NULL, &glo) != 0) {
+		LOG_ERROR("glob failed for RAPL paths: (%s)\n", strerror(errno));
+		return false;
+	}
+
+	/* If the glob doesn't find anything, this most likely means we don't
+	 * have an Intel CPU or we have a kernel which does not support RAPL on
+	 * our CPU.
+	 */
+	if (glo.gl_pathc < 1) {
+		LOG_ONCE(MSG,
+		         "Intel RAPL interface not found in sysfs. "
+		         "This is only problematic if you expected Intel iGPU "
+		         "power threshold optimization.");
+		globfree(&glo);
+		return false;
+	}
+
+	/* Walk the glob set */
+	for (size_t i = 0; i < glo.gl_pathc; i++) {
+		char name[32];
+		if (!read_file_in_dir(glo.gl_pathv[i], "name", name, sizeof(name))) {
+			return false;
+		}
+
+		/* We're searching for the directory where the file named "name"
+		 * contains the contents rapl_name. */
+		if (strncmp(name, rapl_name, sizeof(name)) != 0) {
+			continue;
+		}
+
+		char energy_uj_str[32];
+		if (!read_file_in_dir(glo.gl_pathv[i], "energy_uj", energy_uj_str, sizeof(energy_uj_str))) {
+			return false;
+		}
+
+		char *end = NULL;
+		long long energy_uj_ll = strtoll(energy_uj_str, &end, 10);
+		if (end == energy_uj_str) {
+			LOG_ERROR("Invalid energy_uj contents: %s\n", energy_uj_str);
+			return false;
+		}
+
+		if (energy_uj_ll < 0) {
+			LOG_ERROR("Value of energy_uj is out of expected bounds: %lld\n", energy_uj_ll);
+			return false;
+		}
+
+		/* Go ahead and clamp to 32 bits.  We assume 32 bits later when
+		 * taking deltas and wrapping at 32 bits is exactly what the Linux
+		 * kernel's turbostat utility does so it's probably right.
+		 */
+		*energy_uj = (uint32_t)energy_uj_ll;
+		return true;
+	}
+
+	/* If we got here then the CPU and Kernel support RAPL and all our file
+	 * access has succeeded but we failed to find an entry with the right
+	 * name.  This most likely means we're asking for "uncore" but are on a
+	 * machine that doesn't have an integrated GPU.
+	 */
+	return false;
+}
+
+bool get_cpu_energy_uj(uint32_t *energy_uj)
+{
+	return get_energy_uj("core", energy_uj);
+}
+
+bool get_igpu_energy_uj(uint32_t *energy_uj)
+{
+	return get_energy_uj("uncore", energy_uj);
+}

common/common-power.h

@@ -0,0 +1,45 @@
+/*
+
+Copyright (c) 2017-2019, Feral Interactive
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+ * Redistributions of source code must retain the above copyright notice,
+   this list of conditions and the following disclaimer.
+ * Redistributions in binary form must reproduce the above copyright
+   notice, this list of conditions and the following disclaimer in the
+   documentation and/or other materials provided with the distribution.
+ * Neither the name of Feral Interactive nor the names of its contributors
+   may be used to endorse or promote products derived from this software
+   without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGE.
+
+ */
+
+#pragma once
+
+#include <stdbool.h>
+#include <stdint.h>
+
+/**
+ * Get the amount of energy used to date by the CPU in microjoules
+ */
+bool get_cpu_energy_uj(uint32_t *energy_uj);
+
+/**
+ * Get the amount of energy used to date by the integrated GPU in microjoules
+ */
+bool get_igpu_energy_uj(uint32_t *energy_uj);

common/meson.build

@@ -6,6 +6,7 @@ common_sources = [
     'common-helpers.c',
     'common-gpu.c',
     'common-pidfds.c',
+    'common-power.c',
 ]
 
 daemon_common = static_library(