kernel/linux.git/tools/testing/selftests/resctrl/resctrlfs.c, branch v6.1.168

selftests/resctrl: Extend CPU vendor detection

2022-04-25T22:57:50+00:00

Currently, the resctrl_tests only has a function to detect AMD vendor. Since when the Intel Sub-NUMA Clustering feature is enabled, Intel CMT and MBM counters may not be accurate, the resctrl_tests also need a function to detect Intel vendor. And in the future, resctrl_tests will need a function to detect different vendors, such as Arm. Extend the function to detect Intel vendor as well. Also, this function can be easily extended to detect other vendors. Signed-off-by: Shaopeng Tan Reviewed-by: Reinette Chatre Reviewed-by: Shuah Khan Signed-off-by: Shuah Khan

selftests/resctrl: Change a few printed messages

2021-04-07T22:37:49+00:00

Change a few printed messages to report test progress more clearly. Add a missing "\n" at the end of one printed message. Suggested-by: Shuah Khan Signed-off-by: Fenghua Yu Signed-off-by: Shuah Khan

selftests/resctrl: Fix unmount resctrl FS

2021-04-02T19:58:26+00:00

umount_resctrlfs() directly attempts to unmount resctrl file system without checking if resctrl FS is already mounted or not. It returns 0 on success and on failure it prints an error message and returns an error status. Calling umount_resctrlfs() when resctrl FS isn't mounted will return an error status. There could be situations where-in the caller might not know if resctrl FS is already mounted or not and the caller might still want to unmount resctrl FS if it's already mounted (For example during teardown). To support above use cases, change umount_resctrlfs() such that it now first checks if resctrl FS is already mounted or not and unmounts resctrl FS only if it's already mounted. unmount resctrl FS upon exit. For example, running only mba test on a Broadwell (BDW) machine (MBA isn't supported on BDW CPU). This happens because validate_resctrl_feature_request() would mount resctrl FS to check if mba is enabled on the platform or not and finds that the H/W doesn't support mba and hence will return false to run_mba_test(). This in turn makes the main() function return without unmounting resctrl FS. Tested-by: Babu Moger Signed-off-by: Fenghua Yu Signed-off-by: Shuah Khan

selftests/resctrl: Use resctrl/info for feature detection

2021-04-02T19:57:57+00:00

Resctrl test suite before running any unit test (like cmt, cat, mbm and mba) should first check if the feature is enabled (by kernel and not just supported by H/W) on the platform or not. validate_resctrl_feature_request() is supposed to do that. This function intends to grep for relevant flags in /proc/cpuinfo but there are several issues here 1. validate_resctrl_feature_request() calls fgrep() to get flags from /proc/cpuinfo. But, fgrep() can only return a string with maximum of 255 characters and hence the complete cpu flags are never returned. 2. The substring search logic is also busted. If strstr() finds requested resctrl feature in the cpu flags, it returns pointer to the first occurrence. But, the logic negates the return value of strstr() and hence validate_resctrl_feature_request() returns false if the feature is present in the cpu flags and returns true if the feature is not present. 3. validate_resctrl_feature_request() checks if a resctrl feature is reported in /proc/cpuinfo flags or not. Having a cpu flag means that the H/W supports the feature, but it doesn't mean that the kernel enabled it. A user could selectively enable only a subset of resctrl features using kernel command line arguments. Hence, /proc/cpuinfo isn't a reliable source to check if a feature is enabled or not. The 3rd issue being the major one and fixing it requires changing the way validate_resctrl_feature_request() works. Since, /proc/cpuinfo isn't the right place to check if a resctrl feature is enabled or not, a more appropriate place is /sys/fs/resctrl/info directory. Change validate_resctrl_feature_request() such that, 1. For cat, check if /sys/fs/resctrl/info/L3 directory is present or not 2. For mba, check if /sys/fs/resctrl/info/MB directory is present or not 3. For cmt, check if /sys/fs/resctrl/info/L3_MON directory is present and check if /sys/fs/resctrl/info/L3_MON/mon_features has llc_occupancy 4. For mbm, check if /sys/fs/resctrl/info/L3_MON directory is present and check if /sys/fs/resctrl/info/L3_MON/mon_features has mbm__bytes Please note that only L3_CAT, L3_CMT, MBA and MBM are supported. CDP and L2 variants can be added later. Reported-by: Reinette Chatre Tested-by: Babu Moger Signed-off-by: Fenghua Yu Signed-off-by: Shuah Khan

selftests/resctrl: Check for resctrl mount point only if resctrl FS is supported

2021-04-02T19:57:49+00:00

check_resctrlfs_support() does the following 1. Checks if the platform supports resctrl file system or not by looking for resctrl in /proc/filesystems 2. Calls opendir() on default resctrl file system path (i.e. /sys/fs/resctrl) 3. Checks if resctrl file system is mounted or not by looking at /proc/mounts Steps 2 and 3 will fail if the platform does not support resctrl file system. So, there is no need to check for them if step 1 fails. Fix this by returning immediately if the platform does not support resctrl file system. Tested-by: Babu Moger Signed-off-by: Fenghua Yu Signed-off-by: Shuah Khan

selftests/resctrl: Call kselftest APIs to log test results

2021-04-02T19:54:08+00:00

Call kselftest APIs instead of using printf() to log test results for cleaner code and better future extension. Suggested-by: Shuah Khan Tested-by: Babu Moger Signed-off-by: Fenghua Yu Signed-off-by: Shuah Khan

selftests/resctrl: Rename CQM test as CMT test

2021-04-02T19:53:54+00:00

CMT (Cache Monitoring Technology) [1] is a H/W feature that reports cache occupancy of a process. resctrl selftest suite has a unit test to test CMT for LLC but the test is named as CQM (Cache Quality Monitoring). Furthermore, the unit test source file is named as cqm_test.c and several functions, variables, comments, preprocessors and statements widely use "cqm" as either suffix or prefix. This rampant misusage of CQM for CMT might confuse someone who is newly looking at resctrl selftests because this feature is named CMT in the Intel Software Developer's Manual. Hence, rename all the occurrences (unit test source file name, functions, variables, comments and preprocessors) of cqm with cmt. [1] Please see Intel SDM, Volume 3, chapter 17 and section 18 for more information on CMT: https://software.intel.com/content/www/us/en/develop/articles/intel-sdm.html Suggested-by: Reinette Chatre Tested-by: Babu Moger Signed-off-by: Fenghua Yu Signed-off-by: Shuah Khan

selftests/resctrl: Ensure sibling CPU is not same as original CPU

2021-04-02T19:51:43+00:00

The resctrl tests can accept a CPU on which the tests are run and use default of CPU #1 if it is not provided. In the CAT test a "sibling CPU" is determined that is from the same package where another thread will be run. The current algorithm with which a "sibling CPU" is determined does not take the provided/default CPU into account and when that CPU is the first CPU in a package then the "sibling CPU" will be selected to be the same CPU since it starts by picking the first CPU from core_siblings_list. Fix the "sibling CPU" selection by taking the provided/default CPU into account and ensuring a sibling that is a different CPU is selected. Tested-by: Babu Moger Signed-off-by: Reinette Chatre Signed-off-by: Fenghua Yu Signed-off-by: Shuah Khan

selftests/resctrl: Clean up resctrl features check

2021-04-02T19:51:36+00:00

Checking resctrl features call strcmp() to compare feature strings (e.g. "mba", "cat" etc). The checkings are error prone and don't have good coding style. Define the constant strings in macros and call strncmp() to solve the potential issues. Suggested-by: Shuah Khan Tested-by: Babu Moger Signed-off-by: Fenghua Yu Signed-off-by: Shuah Khan

selftests/resctrl: Fix compilation issues for global variables

2021-04-02T19:51:24+00:00

Reinette reported following compilation issue on Fedora 32, gcc version 10.1.1 /usr/bin/ld: cqm_test.o:/cqm_test.c:22: multiple definition of `cache_size'; cat_test.o:/cat_test.c:23: first defined here The same issue is reported for long_mask, cbm_mask, count_of_bits etc variables as well. Compiler isn't happy because these variables are defined globally in two .c files namely cqm_test.c and cat_test.c and the compiler during compilation finds that the variable is already defined (multiple definition error). Taking a closer look at the usage of these variables reveals that these variables are used only locally in functions such as cqm_resctrl_val() (defined in cqm_test.c) and cat_perf_miss_val() (defined in cat_test.c). These variables are not shared between those functions. So, there is no need for these variables to be global. Hence, fix this issue by making them static variables. Reported-by: Reinette Chatre Tested-by: Babu Moger Signed-off-by: Fenghua Yu Signed-off-by: Shuah Khan