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power: read P-state turbo percentage from sysfs

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If DPDK applications should be used with a minimal set of privileges,
using the msr kernel module on linux should not be necessary.

Since at least kernel 4.4 the rdmsr call to obtain the last non-turbo
boost frequency can be left out, if the sysfs interface is used.
Also RHEL 7 with recent kernel updates should include the sysfs interface
for this (I only looked this up for CentOS 7).

Signed-off-by: Markus Theil <markus.theil@tu-ilmenau.de>
Tested-by: David Hunt <david.hunt@intel.com>
Acked-by: David Hunt <david.hunt@intel.com>
This commit is contained in:
Markus Theil 2022-08-25 20:22:40 +02:00 committed by Thomas Monjalon
parent 0744f1c9f9
commit de254dac60
1 changed files with 50 additions and 29 deletions
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79
lib/power/power_pstate_cpufreq.c
View File

@ -3,6 +3,7 @@
*/
#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <string.h>
#include <unistd.h>
@ -35,15 +36,9 @@
"/sys/devices/system/cpu/cpu%u/cpufreq/cpuinfo_min_freq"
#define POWER_SYSFILE_BASE_FREQ \
"/sys/devices/system/cpu/cpu%u/cpufreq/base_frequency"
#define POWER_SYSFILE_TURBO_PCT \
"/sys/devices/system/cpu/intel_pstate/turbo_pct"
#define POWER_PSTATE_DRIVER "intel_pstate"
#define POWER_MSR_PATH "/dev/cpu/%u/msr"
/*
* MSR related
*/
#define PLATFORM_INFO 0x0CE
#define NON_TURBO_MASK 0xFF00
#define NON_TURBO_OFFSET 0x8
enum power_state {
@ -74,37 +69,41 @@ struct pstate_power_info {
static struct pstate_power_info lcore_power_info[RTE_MAX_LCORE];
/**
* It is to read the specific MSR.
* It is to read the turbo mode percentage from sysfs
*/
static int32_t
power_rdmsr(int msr, uint64_t *val, unsigned int lcore_id)
power_read_turbo_pct(uint64_t *outVal)
{
int fd, ret;
char fullpath[PATH_MAX];
char val[4] = {0};
char *endptr;
snprintf(fullpath, sizeof(fullpath), POWER_MSR_PATH, lcore_id);
fd = open(fullpath, O_RDONLY);
fd = open(POWER_SYSFILE_TURBO_PCT, O_RDONLY);
if (fd < 0) {
RTE_LOG(ERR, POWER, "Error opening '%s': %s\n", fullpath,
RTE_LOG(ERR, POWER, "Error opening '%s': %s\n", POWER_SYSFILE_TURBO_PCT,
strerror(errno));
return fd;
}
ret = pread(fd, val, sizeof(uint64_t), msr);
ret = read(fd, val, sizeof(val));
if (ret < 0) {
RTE_LOG(ERR, POWER, "Error reading '%s': %s\n", fullpath,
RTE_LOG(ERR, POWER, "Error reading '%s': %s\n", POWER_SYSFILE_TURBO_PCT,
strerror(errno));
goto out;
}
POWER_DEBUG_TRACE("MSR Path %s, offset 0x%X for lcore %u\n",
fullpath, msr, lcore_id);
errno = 0;
*outVal = (uint64_t) strtol(val, &endptr, 10);
if (*endptr != 0 || errno != 0) {
RTE_LOG(ERR, POWER, "Error converting str to digits, read from %s: %s\n",
POWER_SYSFILE_TURBO_PCT, strerror(errno));
ret = -1;
goto out;
}
POWER_DEBUG_TRACE("Ret value %d, content is 0x%"PRIx64"\n", ret, *val);
POWER_DEBUG_TRACE("power turbo pct: %"PRIu64"\n", *outVal);
out: close(fd);
return ret;
@ -116,8 +115,9 @@ out: close(fd);
static int
power_init_for_setting_freq(struct pstate_power_info *pi)
{
FILE *f_base = NULL, *f_base_max = NULL, *f_min = NULL, *f_max = NULL;
uint32_t base_ratio, base_max_ratio;
FILE *f_base = NULL, *f_base_min = NULL, *f_base_max = NULL,
*f_min = NULL, *f_max = NULL;
uint32_t base_ratio, base_min_ratio, base_max_ratio;
uint64_t max_non_turbo;
int ret;
@ -130,6 +130,14 @@ power_init_for_setting_freq(struct pstate_power_info *pi)
goto err;
}
open_core_sysfs_file(&f_base_min, "r", POWER_SYSFILE_BASE_MIN_FREQ,
pi->lcore_id);
if (f_base_min == NULL) {
RTE_LOG(ERR, POWER, "failed to open %s\n",
POWER_SYSFILE_BASE_MIN_FREQ);
goto err;
}
open_core_sysfs_file(&f_min, "rw+", POWER_SYSFILE_MIN_FREQ,
pi->lcore_id);
if (f_min == NULL) {
@ -158,6 +166,14 @@ power_init_for_setting_freq(struct pstate_power_info *pi)
goto err;
}
/* read base min ratio */
ret = read_core_sysfs_u32(f_base_min, &base_min_ratio);
if (ret < 0) {
RTE_LOG(ERR, POWER, "Failed to read %s\n",
POWER_SYSFILE_BASE_MIN_FREQ);
goto err;
}
/* base ratio may not exist */
if (f_base != NULL) {
ret = read_core_sysfs_u32(f_base, &base_ratio);
@ -170,20 +186,22 @@ power_init_for_setting_freq(struct pstate_power_info *pi)
base_ratio = 0;
}
/* Add MSR read to detect turbo status */
if (power_rdmsr(PLATFORM_INFO, &max_non_turbo, pi->lcore_id) < 0)
goto err;
/* no errors after this point */
/* convert ratios to bins */
base_max_ratio /= BUS_FREQ;
base_min_ratio /= BUS_FREQ;
base_ratio /= BUS_FREQ;
/* assign file handles */
pi->f_cur_min = f_min;
pi->f_cur_max = f_max;
max_non_turbo = (max_non_turbo&NON_TURBO_MASK)>>NON_TURBO_OFFSET;
/* try to get turbo from global sysfs entry for less privileges than from MSR */
if (power_read_turbo_pct(&max_non_turbo) < 0)
goto err;
/* no errors after this point */
max_non_turbo = base_min_ratio
+ (100 - max_non_turbo) * (base_max_ratio - base_min_ratio) / 100;
POWER_DEBUG_TRACE("no turbo perf %"PRIu64"\n", max_non_turbo);
@ -214,12 +232,15 @@ power_init_for_setting_freq(struct pstate_power_info *pi)
if (f_base != NULL)
fclose(f_base);
fclose(f_base_max);
fclose(f_base_min);
/* f_min and f_max are stored, no need to close */
return 0;
err:
if (f_base != NULL)
fclose(f_base);
if (f_base_min != NULL)
fclose(f_base_min);
if (f_base_max != NULL)
fclose(f_base_max);
if (f_min != NULL)