iMC (Integrated Memory Controller) counters are usually at "/sys/bus/event_source/devices/" and are named as "uncore_imc_<n>". num_of_imcs() function tries to count number of such iMC counters so that it could appropriately initialize required number of perf_attr structures that could be used to read these iMC counters.
num_of_imcs() function assumes that all the directories under this path that start with "uncore_imc" are iMC counters. But, on some systems there could be directories named as "uncore_imc_free_running" which aren't iMC counters. Trying to read from such directories will result in "not found file" errors and MBM/MBA tests will fail.
Hence, fix the logic in num_of_imcs() such that it looks at the first character after "uncore_imc_" to check if it's a numerical digit or not. If it's a digit then the directory represents an iMC counter, else, skip the directory.
Reported-by: Reinette Chatre reinette.chatre@intel.com Signed-off-by: Fenghua Yu fenghua.yu@intel.com --- tools/testing/selftests/resctrl/resctrl_val.c | 22 +++++++++++++++++-- 1 file changed, 20 insertions(+), 2 deletions(-)
diff --git a/tools/testing/selftests/resctrl/resctrl_val.c b/tools/testing/selftests/resctrl/resctrl_val.c index 48bcd5fd7d79..de99d398ebfb 100644 --- a/tools/testing/selftests/resctrl/resctrl_val.c +++ b/tools/testing/selftests/resctrl/resctrl_val.c @@ -221,8 +221,8 @@ static int read_from_imc_dir(char *imc_dir, int count) */ static int num_of_imcs(void) { + char imc_dir[512], *temp; unsigned int count = 0; - char imc_dir[512]; struct dirent *ep; int ret; DIR *dp; @@ -230,7 +230,25 @@ static int num_of_imcs(void) dp = opendir(DYN_PMU_PATH); if (dp) { while ((ep = readdir(dp))) { - if (strstr(ep->d_name, UNCORE_IMC)) { + temp = strstr(ep->d_name, UNCORE_IMC); + if (!temp) + continue; + + /* + * imc counters are named as "uncore_imc_<n>", hence + * increment the pointer to point to <n>. Note that + * sizeof(UNCORE_IMC) would count for null character as + * well and hence the last underscore character in + * uncore_imc'_' need not be counted. + */ + temp = temp + sizeof(UNCORE_IMC); + + /* + * Some directories under "DYN_PMU_PATH" could have + * names like "uncore_imc_free_running", hence, check if + * first character is a numerical digit or not. + */ + if (temp[0] >= '0' && temp[0] <= '9') { sprintf(imc_dir, "%s/%s/", DYN_PMU_PATH, ep->d_name); ret = read_from_imc_dir(imc_dir, count);