Feature checking done by resctrl_mon_feature_exists() covers features
represented by the feature name presence inside the 'mon_features' file
in /sys/fs/resctrl/info/L3_MON directory. There exists a different way
to represent feature support and that is by the presence of 0 or 1 in a
single file in the info/resource directory. In this case the filename
represents what feature support is being indicated.

Add a generic function to check file presence in the
/sys/fs/resctrl/info/<RESOURCE> directory.

Signed-off-by: Maciej Wieczor-Retman <maciej.wieczor-retman@intel.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

validate_resctrl_feature_request() is used to test both if a resource is
present in the info directory, and if a passed monitoring feature is
present in the mon_features file.

Refactor validate_resctrl_feature_request() into two smaller functions
that each accomplish one check to give feature checking more
granularity:
- Resource directory presence in the /sys/fs/resctrl/info directory.
- Feature name presence in the /sys/fs/resctrl/info/<RESOURCE>/mon_features
  file.

Signed-off-by: Maciej Wieczor-Retman <maciej.wieczor-retman@intel.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

The CAT non-contiguous selftests have to read the file responsible for
reporting support of non-contiguous CBMs in kernel (resctrl). Then the
test compares if that information matches what is reported by CPUID
output.

Add a generic helper function to read an unsigned number from
/sys/fs/resctrl/info/<RESOURCE>/<FILE>.

Signed-off-by: Maciej Wieczor-Retman <maciej.wieczor-retman@intel.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

Domain id is acquired differently depending on CPU. AMD tests use id
from L3 cache, whereas CPUs from other vendors base the id on topology
package id. In order to support L2 CAT test, this has to be
generalized.

The driver side code seems to get the domain ids from cache ids so the
approach used by the AMD branch seems to match the kernel-side code. It
will also work with L2 domain IDs as long as the cache level is
generalized.

Using the topology id was always fragile due to mismatch with the
kernel-side way to acquire the domain id. It got incorrect domain id,
e.g., when Cluster-on-Die (CoD) is enabled for CPU (but CoD is not well
suited for resctrl in the first place so it has not been a big issue if
tests don't work correctly with it).

Taking all the above into account, generalize acquiring the domain id
by taking it from the cache id and do not hard-code the cache level.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

Kernel-side calls the instances of a resource domains.

Change the resource_id naming in the selftest code to domain_id to
match the kernel side better.

Suggested-by: Maciej Wieczór-Retman <maciej.wieczor-retman@intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

"L2"/"L3" conversion to integer is embedded into get_cache_size()
which prevents reuse.

Create a helper for the cache string to integer conversion to make
it reusable.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

write_schemata() takes the test name as an argument and determines the
relevant resource based on the test name. Such mapping from name to
resource does not really belong to resctrlfs.c that should provide
only generic, test-independent functions.

Pass the resource stored in the test information structure to
write_schemata() instead of the test name. The new API is also more
flexible as it enables to use write_schemata() for more than one
resource within a test.

While touching the sprintf(), move the unnecessary %c that is always
'=' directly into the format string.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

Each test currently has a "run test" function in per test file and
another resctrl_tests.c. The functions in resctrl_tests.c are almost
identical.

Generalize the one in resctrl_tests.c such that it can be shared
between all of the tests. It makes adding new tests easier and removes
the per test if () forests.

Also add comment to CPU vendor IDs that they must be defined as bits
for a bitmask.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

CAT test does not reset the CPU affinity after the benchmark.
This is relatively harmless as is because CAT test is the last
benchmark to run, however, more tests may be added later.

Store the CPU affinity the first time taskset_benchmark() is run and
add taskset_restore() which the test can call to reset the CPU mask to
its original value.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

CAT test spawns two processes into two different control groups with
exclusive schemata. Both the processes alloc a buffer from memory
matching their allocated LLC block size and flush the entire buffer out
of caches. Since the processes are reading through the buffer only once
during the measurement and initially all the buffer was flushed, the
test isn't testing CAT.

Rewrite the CAT test to allocate a buffer sized to half of LLC. Then
perform a sequence of tests with different LLC alloc sizes starting
from half of the CBM bits down to 1-bit CBM. Flush the buffer before
each test and read the buffer twice. Observe the LLC misses on the
second read through the buffer. As the allocated LLC block gets smaller
and smaller, the LLC misses will become larger and larger giving a
strong signal on CAT working properly.

The new CAT test is using only a single process because it relies on
measured effect against another run of itself rather than another
process adding noise. The rest of the system is set to use the CBM bits
not used by the CAT test to keep the test isolated.

Replace count_bits() with count_contiguous_bits() to get the first bit
position in order to be able to calculate masks based on it.

This change has been tested with a number of systems from different
generations.

Suggested-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>