From 4db9587bbf726a658807089e0af162208e9bd2ee Mon Sep 17 00:00:00 2001 From: David Hunt Date: Tue, 16 Mar 2021 09:38:11 +0000 Subject: [PATCH] power: check 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 --- lib/librte_power/power_pstate_cpufreq.c | 40 ++++++++++++++++++++++--- 1 file changed, 36 insertions(+), 4 deletions(-) diff --git a/lib/librte_power/power_pstate_cpufreq.c b/lib/librte_power/power_pstate_cpufreq.c index edf6328e5f..8a1fffaed5 100644 --- a/lib/librte_power/power_pstate_cpufreq.c +++ b/lib/librte_power/power_pstate_cpufreq.c @@ -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. -- 2.20.1