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power: check sysfs base frequency

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Some kernels may show in incorrect value for base frequency in
sysfs (e.g. 15 GHz). This throws off the SST-BF algorithm for
high and low priority cores. So if base_frequency is greater
than max turbo frequency, ignore, and handle it as a normal
core.

Known Kernel version with issue: Linux 5.8.7

Signed-off-by: David Hunt <david.hunt@intel.com>
This commit is contained in:
David Hunt 2021-03-16 09:38:11 +00:00 committed by Thomas Monjalon
parent f38913b7fb
commit 4db9587bbf
1 changed files with 36 additions and 4 deletions
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40
lib/librte_power/power_pstate_cpufreq.c
View File

@ -154,29 +154,49 @@ out: close(fd);
static int
power_init_for_setting_freq(struct pstate_power_info *pi)
{
FILE *f_min, *f_max, *f_base;
FILE *f_min, *f_max, *f_base = NULL, *f_base_max;
char fullpath_min[PATH_MAX];
char fullpath_max[PATH_MAX];
char fullpath_base[PATH_MAX];
char fullpath_base_max[PATH_MAX];
char buf_base[BUFSIZ];
char *s_base;
char *s_base_max;
uint32_t base_ratio = 0;
uint32_t base_max_ratio = 0;
uint64_t max_non_turbo = 0;
int ret_val = 0;
snprintf(fullpath_base_max,
sizeof(fullpath_base_max),
POWER_SYSFILE_BASE_MAX_FREQ,
pi->lcore_id);
f_base_max = fopen(fullpath_base_max, "r");
FOPEN_OR_ERR_RET(f_base_max, -1);
if (f_base_max != NULL) {
s_base_max = fgets(buf_base, sizeof(buf_base), f_base_max);
FOPS_OR_NULL_GOTO(s_base_max, out);
buf_base[BUFSIZ-1] = '\0';
if (strlen(buf_base))
/* Strip off terminating '\n' */
strtok(buf_base, "\n");
base_max_ratio =
strtoul(buf_base, NULL, POWER_CONVERT_TO_DECIMAL)
/ BUS_FREQ;
}
snprintf(fullpath_min, sizeof(fullpath_min), POWER_SYSFILE_MIN_FREQ,
pi->lcore_id);
f_min = fopen(fullpath_min, "rw+");
FOPEN_OR_ERR_RET(f_min, -1);
snprintf(fullpath_max, sizeof(fullpath_max), POWER_SYSFILE_MAX_FREQ,
pi->lcore_id);
f_max = fopen(fullpath_max, "rw+");
if (f_max == NULL)
fclose(f_min);
FOPEN_OR_ERR_RET(f_max, -1);
pi->f_cur_min = f_min;
@ -186,6 +206,7 @@ power_init_for_setting_freq(struct pstate_power_info *pi)
pi->lcore_id);
f_base = fopen(fullpath_base, "r");
FOPEN_OR_ERR_RET(f_base, -1);
if (f_base == NULL) {
/* No sysfs base_frequency, that's OK, continue without */
base_ratio = 0;
@ -215,6 +236,17 @@ power_init_for_setting_freq(struct pstate_power_info *pi)
pi->non_turbo_max_ratio = max_non_turbo;
/*
* If base_frequency is reported as greater than the maximum
* turbo frequency, that's a known issue with some kernels.
* Set base_frequency to max_non_turbo as a workaround.
*/
if (base_ratio > base_max_ratio) {
/* base_ratio is greater than max turbo. Kernel bug. */
pi->priority_core = 0;
goto out;
}
/*
* If base_frequency is reported as greater than the maximum
* non-turbo frequency, then mark it as a high priority core.