lib/power: add check for sysfs base frequency
PATCH 1/1 lib/power: add check for sysfs base frequency
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 <[email protected]>
--- lib/librte_power/power_pstate_cpufreq.c | 40 ++++++++++++++++++++++--- 1 file changed, 36 insertions(+), 4 deletions(-)
lib/librte_power/power_pstate_cpufreq.c +36 -4
@@ -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_min,sizeof (fullpath_min),POWER_SYSFILE_MIN_FREQ , +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.
Signature · 1 line
2.17.1
Thomas Monjalon
Applied16/03/2021 10:38, David Hunt:
Quoted 9 lines
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_frequencyis 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 <[email protected]>
Applied, thanks