Added support for Zen/Zen3 RAPL package power sensor.

zen3-rapl.c

@@ -0,0 +1,112 @@
+#include <stdio.h>
+#include <unistd.h>
+#include <cpuid.h>
+#include <math.h>
+#include <string.h>
+#include <fcntl.h>
+
+#include "zen3-rapl.h"
+
+#define AMD_STRING "AuthenticAMD"
+#define ZEN_FAMILY 0x17
+#define ZEN3_FAMILY 0x19
+
+#define MEASUREMENT_TIME 0.25
+
+static float energy_unit = 0;
+
+static int msr_file = -1;
+
+static float package_power = 0.0;
+
+static int check_zen()
+{
+    unsigned int eax = 0, ebx = 0, ecx = 0, edx = 0, ext_family;
+    char vendor[13];
+
+    __get_cpuid(0, &eax, &ebx, &ecx, &edx);
+
+    memcpy(vendor, &ebx, 4);
+    memcpy(vendor+4, &edx, 4);
+    memcpy(vendor+8, &ecx, 4);
+    vendor[12] = 0;
+
+    if (strcmp(vendor, AMD_STRING) != 0){
+        return 0;
+    }
+
+    __get_cpuid(1, &eax, &ebx, &ecx, &edx);
+
+    ext_family = ((eax >> 8) & 0xF) + ((eax >> 20) & 0xFF);
+    if (ext_family != ZEN_FAMILY && ext_family != ZEN3_FAMILY){
+        return 0;
+    }
+
+    return 1;
+}
+
+static int read_msr(int file, unsigned int index, unsigned long long *data)
+{
+    if (file < 0)
+        return 0;
+
+    return pread(file, data, sizeof *data, index) == sizeof *data;
+}
+
+static float get_energy_unit()
+{
+    unsigned long long data;
+    // AMD OSRR: page 139 - MSRC001_0299
+    if (!read_msr(msr_file, 0xC0010299, &data))
+        return 0.0;
+
+    return pow(1.0/2.0, (float)((data >> 8) & 0x1F));
+}
+
+static unsigned long get_package_energy()
+{
+    unsigned long long data;
+    // AMD OSRR: page 139 - MSRC001_029B
+    if (!read_msr(msr_file, 0xC001029B, &data))
+        return 0;
+
+    return data;
+}
+
+int init_rapl()
+{
+	/* Check for supported Zen CPU */
+	if (!check_zen())
+		return 0;
+	
+	/* Open MSR file */
+	char *msr_path = "/dev/cpu/0/msr";
+    msr_file = open(msr_path, O_RDONLY);
+	if (msr_file < 0)
+		return 0;
+	
+	/* Energy unit */
+	energy_unit = get_energy_unit();
+    if (energy_unit == 0)
+        return 0;
+	
+	return 1;
+}
+
+float get_rapl_package_power()
+{
+	unsigned long package_eng_b = 0;
+	unsigned long package_eng_a = 0;
+
+    package_eng_b = get_package_energy();
+
+    usleep(MEASUREMENT_TIME*1000000);
+
+    package_eng_a = get_package_energy();
+
+	/* Only update if we computed a good power reading, otherwise return the most recent measurement */
+    if (package_eng_a >= package_eng_b)
+        package_power = (package_eng_a - package_eng_b) * energy_unit / MEASUREMENT_TIME;
+	
+	return package_power;
+}