Commit d81343b5 authored Mar 17, 2021 by Fenghua Yu Committed by Shuah Khan Apr 02, 2021

selftests/resctrl: Fix incorrect parsing of iMC counters



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>
Tested-by: Babu Moger <babu.moger@amd.com>
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

parent 4e5cb354

tools/testing/selftests/resctrl/resctrl_val.c

+20 −2

Original line number	Diff line number	Diff line
		@@ -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);