linux-toradex.git/tools/testing/selftests/resctrl/resctrl.h, branch v5.19-rc4

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: 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: Share show_cache_info() by CAT and CMT tests

2021-04-02T19:54:14+00:00

show_cache_info() functions are defined separately in CAT and CMT
tests. But the functions are same for the tests and unnecessary
to be defined separately. Share the function by the tests.

Suggested-by: Shuah Khan 
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: 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 other global variables

2021-04-02T19:51:30+00:00

Reinette reported following compilation issue on Fedora 32, gcc version
10.1.1

/usr/bin/ld: resctrl_tests.o:/resctrl.h:65: multiple definition
of `bm_pid'; cache.o:/resctrl.h:65: first defined here

Other variables are ppid, tests_run, llc_occup_path, is_amd. Compiler
isn't happy because these variables are defined globally in two .c files
but are not declared as extern.

To fix issues for the global variables, declare them as extern.

Chang Log:
- Split this patch from v4's patch 1 (Shuah).

Reported-by: Reinette Chatre 
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

selftests/resctrl: Add vendor detection mechanism

2020-02-11T01:43:17+00:00

RESCTRL feature is supported both on Intel and AMD now. Some features
are implemented differently. Add vendor detection mechanism. Use the vendor
check where there are differences.

Signed-off-by: Babu Moger 
Co-developed-by: Fenghua Yu 
Signed-off-by: Fenghua Yu 
Signed-off-by: Shuah Khan

selftests/resctrl: Add Cache Allocation Technology (CAT) selftest

2020-02-11T01:43:07+00:00

Cache Allocation Technology (CAT) selftest allocates a portion of
last level cache and starts a benchmark to read each cache
line in this portion of cache. Measure the cache misses in perf and
the misses should be equal to the number of cache lines in this
portion of cache.

We don't use CQM to calculate cache usage because some CAT enabled
platforms don't have CQM.

Co-developed-by: Sai Praneeth Prakhya 
Signed-off-by: Sai Praneeth Prakhya 
Co-developed-by: Babu Moger 
Signed-off-by: Babu Moger 
Signed-off-by: Fenghua Yu 
Signed-off-by: Shuah Khan