kernel/linux.git/tools/testing/selftests/resctrl/cmt_test.c, branch v6.19.11

selftests/resctrl: Discover SNC kernel support and adjust messages

2025-01-15T00:06:32+00:00

Resctrl selftest prints a message on test failure that Sub-Numa Clustering (SNC) could be enabled and points the user to check their BIOS settings. No actual check is performed before printing that message so it is not very accurate in pinpointing a problem. When there is SNC support for kernel's resctrl subsystem and SNC is enabled then sub node files are created for each node in the resctrlfs. The sub node files exist in each regular node's L3 monitoring directory. The reliable path to check for existence of sub node files is /sys/fs/resctrl/mon_data/mon_L3_00/mon_sub_L3_00. Add helper that checks for mon_sub_L3_00 existence. Correct old messages to account for kernel support of SNC in resctrl. Signed-off-by: Maciej Wieczor-Retman Reviewed-by: Reinette Chatre Signed-off-by: Shuah Khan

selftests/resctrl: Keep results from first test run

2024-11-05T00:02:03+00:00

The resctrl selftests drop the results from every first test run to avoid (per comment) "inaccurate due to monitoring setup transition phase" data. Previously inaccurate data resulted from workloads needing some time to "settle" and also the measurements themselves to account for earlier measurements to measure across needed timeframe. commit da50de0a92f3 ("selftests/resctrl: Calculate resctrl FS derived mem bw over sleep(1) only") ensured that measurements accurately measure just the time frame of interest. The default "fill_buf" benchmark since separated the buffer prepare phase from the benchmark run phase reducing the need for the tests themselves to accommodate the benchmark's "settle" time. With these enhancements there are no remaining portions needing to "settle" and the first test run can contribute to measurements. Signed-off-by: Reinette Chatre Reviewed-by: Ilpo Järvinen Signed-off-by: Shuah Khan

selftests/resctrl: Make benchmark parameter passing robust

2024-11-05T00:02:03+00:00

The benchmark used during the CMT, MBM, and MBA tests can be provided by the user via (-b) parameter, if not provided the default "fill_buf" benchmark is used. The user is additionally able to override any of the "fill_buf" default parameters when running the tests with "-b fill_buf ". The "fill_buf" parameters are managed as an array of strings. Using an array of strings is complex because it requires transformations to/from strings at every producer and consumer. This is made worse for the individual tests where the default benchmark parameters values may not be appropriate and additional data wrangling is required. For example, the CMT test duplicates the entire array of strings in order to replace one of the parameters. More issues appear when combining the usage of an array of strings with the use case of user overriding default parameters by specifying "-b fill_buf ". This use case is fragile with opportunities to trigger a SIGSEGV because of opportunities for NULL pointers to exist in the array of strings. For example, by running below (thus by specifying "fill_buf" should be used but all parameters are NULL): $ sudo resctrl_tests -t mbm -b fill_buf Replace the "array of strings" parameters used for "fill_buf" with new struct fill_buf_param that contains the "fill_buf" parameters that can be used directly without transformations to/from strings. Two instances of struct fill_buf_param may exist at any point in time: * If the user provides new parameters to "fill_buf", the user parameter structure (struct user_params) will point to a fully initialized and immutable struct fill_buf_param containing the user provided parameters. * If "fill_buf" is the benchmark that should be used by a test, then the test parameter structure (struct resctrl_val_param) will point to a fully initialized struct fill_buf_param. The latter may contain (a) the user provided parameters verbatim, (b) user provided parameters adjusted to be appropriate for the test, or (c) the default parameters for "fill_buf" that is appropriate for the test if the user did not provide "fill_buf" parameters nor an alternate benchmark. The existing behavior of CMT test is to use test defined value for the buffer size even if the user provides another value via command line. This behavior is maintained since the test requires that the buffer size matches the size of the cache allocated, and the amount of cache allocated can instead be changed by the user with the "-n" command line parameter. Signed-off-by: Reinette Chatre Reviewed-by: Ilpo Järvinen Signed-off-by: Shuah Khan

selftests/resctrl: Remove test name comparing from write_bm_pid_to_resctrl()

2024-07-11T17:23:54+00:00

write_bm_pid_to_resctrl() uses resctrl_val to check test name which is not a good interface generic resctrl FS functions should provide. Tests define mongrp when needed. Remove the test name check in write_bm_pid_to_resctrl() to only rely on the mongrp parameter being non-NULL. Remove write_bm_pid_to_resctrl() resctrl_val parameter and resctrl_val member from the struct resctrl_val_param that are not used anymore. Similarly, remove the test name constants that are no longer used. Signed-off-by: Ilpo Järvinen Tested-by: Babu Moger Reviewed-by: Reinette Chatre Signed-off-by: Shuah Khan

selftests/resctrl: Remove mongrp from CMT test

2024-07-11T17:23:54+00:00

The CMT selftest instantiates a monitor group to read LLC occupancy. Since the test also creates a control group, it is unnecessary to create another one for monitoring because control groups already provide monitoring too. Remove the unnecessary monitor group from the CMT selftest. Suggested-by: Reinette Chatre Signed-off-by: Ilpo Järvinen Tested-by: Babu Moger Reviewed-by: Reinette Chatre Signed-off-by: Shuah Khan

selftests/resctrl: Add ->init() callback into resctrl_val_param

2024-07-11T17:23:54+00:00

The struct resctrl_val_param is there to customize behavior inside resctrl_val() which is currently not used to full extent and there are number of strcmp()s for test name in resctrl_val done by resctrl_val(). Create ->init() hook into the struct resctrl_val_param to cleanly do per test initialization. Remove also unused branches to setup paths and the related #defines for CMT test. While touching kerneldoc, make the adjacent line consistent with the newly added form (callback vs call back). Signed-off-by: Ilpo Järvinen Tested-by: Babu Moger Reviewed-by: Reinette Chatre Signed-off-by: Shuah Khan

selftests/resctrl: Add ->measure() callback to resctrl_val_param

2024-07-11T17:23:54+00:00

The measurement done in resctrl_val() varies depending on test type. The decision for how to measure is decided based on the string compare to test name which is quite inflexible. Add ->measure() callback into the struct resctrl_val_param to allow each test to provide necessary code as a function which simplifies what resctrl_val() has to do. Signed-off-by: Ilpo Järvinen Tested-by: Babu Moger Reviewed-by: Reinette Chatre Signed-off-by: Shuah Khan

selftests/resctrl: fix clang build warnings related to abs(), labs() calls

2024-05-08T22:53:19+00:00

When building with clang, via: make LLVM=1 -C tools/testing/selftests ...two types of warnings occur: warning: absolute value function 'abs' given an argument of type 'long' but has parameter of type 'int' which may cause truncation of value warning: taking the absolute value of unsigned type 'unsigned long' has no effect Fix these by: a) using labs() in place of abs(), when long integers are involved, and b) Change to use signed integer data types, in places where subtraction is used (and could end up with negative values). c) Remove a duplicate abs() call in cmt_test.c. Cc: Ilpo Järvinen Reviewed-by: Reinette Chatre Signed-off-by: John Hubbard Signed-off-by: Shuah Khan

selftests/resctrl: Move cleanups out of individual tests

2024-05-06T19:57:19+00:00

Every test calls its cleanup function at the end of it's test function. After the cleanup function pointer is added to the test framework this can be simplified to executing the callback function at the end of the generic test running function. Make test cleanup functions static and call them from the end of run_single_test() from the resctrl_test's cleanup function pointer. Signed-off-by: Maciej Wieczor-Retman Reviewed-by: Reinette Chatre Signed-off-by: Shuah Khan

selftests/resctrl: Add cleanup function to test framework

2024-05-06T19:57:19+00:00

Resctrl selftests use very similar functions to cleanup after themselves. This creates a lot of code duplication. Also not being hooked to the test framework means that ctrl-c handler isn't aware of what test is currently running and executes all cleanups even though only one is needed. Add a function pointer to the resctrl_test struct and attach to it cleanup functions from individual tests. Signed-off-by: Maciej Wieczor-Retman Reviewed-by: Reinette Chatre Signed-off-by: Shuah Khan