evga-icx/zen3-rapl.c

113 lines
2.3 KiB
C

#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;
}