linux-stable.git/tools/testing/selftests/resctrl/resctrl_val.c, branch linux-5.11.y

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

2021-05-12T06:37:25+00:00

[ Upstream commit 1205b688c92558a04d8dd4cbc2b213e0fceba5db ]

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 
Signed-off-by: Sasha Levin

selftests/resctrl: Fix incorrect parsing of iMC counters

2021-05-12T06:37:25+00:00

[ Upstream commit d81343b5eedf84be71a4313e8fd073d0c510afcf ]

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 
Signed-off-by: Sasha Levin

selftests/resctrl: Clean up resctrl features check

2021-05-12T06:37:24+00:00

[ Upstream commit 2428673638ea28fa93d2a38b1c3e8d70122b00ee ]

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 
Signed-off-by: Sasha Levin

selftests/resctrl: Add Cache QoS Monitoring (CQM) selftest

2020-02-11T01:42:57+00:00

Cache QoS Monitoring (CQM) selftest starts stressful cache benchmark
with specified size of memory to access the cache. Last Level cache
occupancy reported by CQM should be close to the size of the memory.

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

selftests/resctrl: Add MBM test

2020-02-11T01:42:29+00:00

MBM (Memory Bandwidth Monitoring) test is the first implemented selftest.
It starts a stressful memory bandwidth benchmark and assigns the
bandwidth pid in a resctrl monitoring group. Read and compare perf IMC
counter and MBM total bytes for the benchmark. The numbers should be
close enough to pass the test.

Default benchmark is built-in fill_buf. But users can specify their
own benchmark by option "-b".

We can add memory bandwidth monitoring for multiple processes in the
future.

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

selftests/resctrl: Add callback to start a benchmark

2020-02-11T01:38:28+00:00

The callback starts a child process and puts the child pid in created
resctrl group with specified memory bandwidth in schemata. The child
starts running benchmark.

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

selftests/resctrl: Read memory bandwidth from perf IMC counter and from resctrl file system

2020-02-11T01:38:08+00:00

Total memory bandwidth can be monitored from perf IMC counter and from
resctrl file system. Later the two will be compared to verify the total
memory bandwidth read from resctrl is correct.

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