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From: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>
To: shuah@kernel.org, skhan@linuxfoundation.org,
	linux-kselftest@vger.kernel.org
Cc: tglx@linutronix.de, mingo@redhat.com, bp@alien8.de,
	tony.luck@intel.com, reinette.chatre@intel.com,
	babu.moger@amd.com, james.morse@arm.com,
	ravi.v.shankar@intel.com, fenghua.yu@intel.com, x86@kernel.org,
	linux-kernel@vger.kernel, dan.carpenter@oracle.com,
	dcb314@hotmail.com,
	Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>
Subject: [PATCH V2 18/19] selftests/resctrl: Fix incorrect parsing of iMC counters
Date: Mon, 18 May 2020 15:08:38 -0700
Message-ID: <ba934b6ef4536f308caa22c2c65299da3e391c59.1589835155.git.sai.praneeth.prakhya@intel.com> (raw)
In-Reply-To: <cover.1589835155.git.sai.praneeth.prakhya@intel.com>

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.

The present code 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 directory would result in "not found
file" errors and MBM/MBA tests would fail.

Hence, change 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: Sai Praneeth Prakhya <sai.praneeth.prakhya@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 270cd95e0026..94f3a34e21bb 100644
--- a/tools/testing/selftests/resctrl/resctrl_val.c
+++ b/tools/testing/selftests/resctrl/resctrl_val.c
@@ -222,7 +222,7 @@ static int read_from_imc_dir(char *imc_dir, int count)
 static int num_of_imcs(void)
 {
 	unsigned int count = 0;
-	char imc_dir[512];
+	char imc_dir[512], *temp;
 	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);
-- 
2.19.1


  parent reply index

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-18 22:08 [PATCH V2 00/19] Miscellaneous fixes for resctrl selftests Sai Praneeth Prakhya
2020-05-18 22:08 ` [PATCH V2 01/19] selftests/resctrl: Rename CQM test as CMT test Sai Praneeth Prakhya
2020-05-18 22:08 ` [PATCH V2 02/19] selftests/resctrl: Fix typo Sai Praneeth Prakhya
2020-05-18 22:08 ` [PATCH V2 03/19] selftests/resctrl: Fix typo in help text Sai Praneeth Prakhya
2020-05-18 22:08 ` [PATCH V2 04/19] selftests/resctrl: Declare global variables as extern Sai Praneeth Prakhya
2020-05-18 22:08 ` [PATCH V2 05/19] selftests/resctrl: Return if resctrl file system is not supported Sai Praneeth Prakhya
2020-05-18 22:08 ` [PATCH V2 06/19] selftests/resctrl: Check for resctrl mount point only if resctrl FS is supported Sai Praneeth Prakhya
2020-05-18 22:08 ` [PATCH V2 07/19] selftests/resctrl: Use resctrl/info for feature detection Sai Praneeth Prakhya
2020-05-18 22:08 ` [PATCH V2 08/19] selftests/resctrl: Ensure sibling CPU is not same as original CPU Sai Praneeth Prakhya
2020-05-18 22:08 ` [PATCH V2 09/19] selftests/resctrl: Fix missing options "-n" and "-p" Sai Praneeth Prakhya
2020-05-18 22:08 ` [PATCH V2 10/19] selftests/resctrl: Fix MBA/MBM results reporting format Sai Praneeth Prakhya
2020-05-18 22:08 ` [PATCH V2 11/19] selftests/resctrl: Abort running tests if not root user Sai Praneeth Prakhya
2020-05-18 22:08 ` [PATCH V2 12/19] selftests/resctrl: Enable gcc checks to detect buffer overflows Sai Praneeth Prakhya
2020-05-18 22:08 ` [PATCH V2 13/19] selftests/resctrl: Dynamically select buffer size for CAT test Sai Praneeth Prakhya
2020-05-18 22:08 ` [PATCH V2 14/19] selftests/resctrl: Skip the test if requested resctrl feature is not supported Sai Praneeth Prakhya
2020-05-20 23:46   ` Reinette Chatre
2020-05-21 17:12     ` Prakhya, Sai Praneeth
2020-05-18 22:08 ` [PATCH V2 15/19] selftests/resctrl: Change return type of umount_resctrlfs() to void Sai Praneeth Prakhya
2020-05-20 23:52   ` Reinette Chatre
2020-05-21 17:19     ` Prakhya, Sai Praneeth
2020-05-21 18:15       ` Reinette Chatre
2020-05-18 22:08 ` [PATCH V2 16/19] selftests/resctrl: Umount resctrl FS only if mounted Sai Praneeth Prakhya
2020-05-18 22:08 ` [PATCH V2 17/19] selftests/resctrl: Unmount resctrl FS after running all tests Sai Praneeth Prakhya
2020-05-18 22:08 ` Sai Praneeth Prakhya [this message]
2020-05-18 22:08 ` [PATCH V2 19/19] selftests/resctrl: Fix checking for < 0 for unsigned values Sai Praneeth Prakhya
2020-05-21 16:12 ` [PATCH V2 00/19] Miscellaneous fixes for resctrl selftests Reinette Chatre
2020-05-21 17:28   ` Prakhya, Sai Praneeth

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