linux/tools/testing/selftests/resctrl, 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: Change a few printed messages

2021-04-07T22:37:49Z

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: Create .gitignore to include resctrl_tests

2021-04-02T19:58:42Z

Create .gitignore to hold the test file resctrl_tests generated after compiling. Suggested-by: Shuah Khan Tested-by: Babu Moger Signed-off-by: Fenghua Yu Signed-off-by: Shuah Khan

selftests/resctrl: Fix checking for < 0 for unsigned values

2021-04-02T19:58:37Z

Dan reported following static checker warnings tools/testing/selftests/resctrl/resctrl_val.c:545 measure_vals() warn: 'bw_imc' unsigned <= 0 tools/testing/selftests/resctrl/resctrl_val.c:549 measure_vals() warn: 'bw_resc_end' unsigned <= 0 These warnings are reported because 1. measure_vals() declares 'bw_imc' and 'bw_resc_end' as unsigned long variables 2. Return value of get_mem_bw_imc() and get_mem_bw_resctrl() are assigned to 'bw_imc' and 'bw_resc_end' respectively 3. The returned values are checked for <= 0 to see if the calls failed Checking for < 0 for an unsigned value doesn't make any sense. Fix this issue by changing the implementation of get_mem_bw_imc() and get_mem_bw_resctrl() such that they now accept reference to a variable and set the variable appropriately upon success and return 0, else return < 0 on error. Reported-by: Dan Carpenter Tested-by: Babu Moger Signed-off-by: Fenghua Yu Signed-off-by: Shuah Khan

selftests/resctrl: Fix incorrect parsing of iMC counters

2021-04-02T19:58:31Z

iMC (Integrated Memory Controller) counters are usually at "/sys/bus/event_source/devices/" and are named as "uncore_imc_". 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 Tested-by: Babu Moger Signed-off-by: Fenghua Yu 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 MBA/MBM results reporting format

2021-04-02T19:58:02Z

MBM unit test starts fill_buf (default built-in benchmark) in a new con_mon group (c1, m1) and records resctrl reported mbm values and iMC (Integrated Memory Controller) values every second. It does this for five seconds (randomly chosen value) in total. It then calculates average of resctrl_mbm values and imc_mbm values and if the difference is greater than 300 MB/sec (randomly chosen value), the test treats it as a failure. MBA unit test is similar to MBM but after every run it changes schemata. Checking for a difference of 300 MB/sec doesn't look very meaningful when the mbm values are changing over a wide range. For example, below are the values running MBA test on SKL with different allocations 1. With 10% as schemata both iMC and resctrl mbm_values are around 2000 MB/sec 2. With 100% as schemata both iMC and resctrl mbm_values are around 10000 MB/sec A 300 MB/sec difference between resctrl_mbm and imc_mbm values is acceptable at 100% schemata but it isn't acceptable at 10% schemata because that's a huge difference. So, fix this by checking for percentage difference instead of absolute difference i.e. check if the difference between resctrl_mbm value and imc_mbm value is within 5% (randomly chosen value) of imc_mbm value. If the difference is greater than 5% of imc_mbm value, treat it is a failure. Tested-by: Babu Moger Signed-off-by: Fenghua Yu Signed-off-by: Shuah Khan