linux/tools/testing/selftests/resctrl/resctrl_tests.c, branch v5.14

selftests/resctrl: Fix incorrect parsing of option "-t"

2021-06-08T00:38:58Z

Resctrl test suite accepts command line argument "-t" to specify the unit tests to run in the test list (e.g., -t mbm,mba,cmt,cat) as documented in the help. When calling strtok() to parse the option, the incorrect delimiters argument ":\t" is used. As a result, passing "-t mbm,mba,cmt,cat" throws an invalid option error. Fix this by using delimiters argument "," instead of ":\t" for parsing of unit tests list. At the same time, remove the unnecessary "spaces" between the unit tests in help documentation to prevent confusion. Fixes: 790bf585b0ee ("selftests/resctrl: Add Cache Allocation Technology (CAT) selftest") Fixes: 78941183d1b1 ("selftests/resctrl: Add Cache QoS Monitoring (CQM) selftest") Fixes: ecdbb911f22d ("selftests/resctrl: Add MBM test") Fixes: 034c7678dd2c ("selftests/resctrl: Add README for resctrl tests") Cc: stable@vger.kernel.org Signed-off-by: Xiaochen Shen Reviewed-by: Tony Luck Signed-off-by: Shuah Khan

selftests/resctrl: Fix unmount resctrl FS

2021-04-02T19:58:26Z

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: Skip the test if requested resctrl feature is not supported

2021-04-02T19:58:20Z

There could be two reasons why a resctrl feature might not be enabled on the platform 1. H/W might not support the feature 2. Even if the H/W supports it, the user might have disabled the feature through kernel command line arguments Hence, any resctrl unit test (like cmt, cat, mbm and mba) before starting the test will first check if the feature is enabled on the platform or not. If the feature isn't enabled, then the test returns with an error status. For example, if MBA isn't supported on a platform and if the user tries to run MBA, the output will look like this ok mounting resctrl to "/sys/fs/resctrl" not ok MBA: schemata change But, not supporting a feature isn't a test failure. So, instead of treating it as an error, use the SKIP directive of the TAP protocol. With the change, the output will look as below ok MBA # SKIP Hardware does not support MBA or MBA is disabled Suggested-by: Reinette Chatre Tested-by: Babu Moger Signed-off-by: Fenghua Yu Signed-off-by: Shuah Khan

selftests/resctrl: Modularize resctrl test suite main() function

2021-04-02T19:58:14Z

Resctrl test suite main() function does the following things 1. Parses command line arguments passed by user 2. Some setup checks 3. Logic that calls into each unit test 4. Print result and clean up after running each unit test Introduce wrapper functions for steps 3 and 4 to modularize the main() function. Adding these wrapper functions makes it easier to add any logic to each individual test. Please note that this is a preparatory patch for the next one and no functional changes are intended. Suggested-by: Reinette Chatre Tested-by: Babu Moger Signed-off-by: Fenghua Yu Signed-off-by: Shuah Khan

selftests/resctrl: Don't hard code value of "no_of_bits" variable

2021-04-02T19:58:08Z

Cache related tests (like CAT and CMT) depend on a variable called no_of_bits to run. no_of_bits defines the number of contiguous bits that should be set in the CBM mask and a user can pass a value for no_of_bits using -n command line argument. If a user hasn't passed any value, it defaults to 5 (randomly chosen value). Hard coding no_of_bits to 5 will make the cache tests fail to run on systems that support maximum cbm mask that is less than or equal to 5 bits. Hence, don't hard code no_of_bits value. If a user passes a value for "no_of_bits" using -n option, use it. Otherwise, no_of_bits is equal to half of the maximum number of bits in the cbm mask. Please note that CMT test is still hard coded to 5 bits. It will change in subsequent patches that change CMT test. Tested-by: Babu Moger Signed-off-by: Fenghua Yu Signed-off-by: Shuah Khan

selftests/resctrl: Fix a printed message

2021-04-02T19:54:20Z

Add a missing newline to the printed help text to improve readability. Tested-by: Babu Moger Signed-off-by: Reinette Chatre Signed-off-by: Fenghua Yu Signed-off-by: Shuah Khan

selftests/resctrl: Call kselftest APIs to log test results

2021-04-02T19:54:08Z

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

2021-04-02T19:53:54Z

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: Fix missing options "-n" and "-p"

2021-04-02T19:53:02Z

resctrl test suite accepts command line arguments (like -b, -t, -n and -p) as documented in the help. But passing -n and -p throws an invalid option error. This happens because -n and -p are missing in the list of characters that getopt() recognizes as valid arguments. Hence, they are treated as invalid options. Fix this by adding them to the list of characters that getopt() recognizes as valid arguments. Please note that the main() function already has the logic to deal with the values passed as part of these arguments and hence no changes are needed there. Tested-by: Babu Moger Signed-off-by: Fenghua Yu Signed-off-by: Shuah Khan

selftests/resctrl: Clean up resctrl features check

2021-04-02T19:51:36Z

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