Reinette Chatre a44c26d7fa selftests/resctrl: Replace magic constants used as array size
The Memory Bandwidth Allocation (MBA) test iterates through all possible
MBA allocations, from 10% (ALLOCATION_MIN) to 100% (ALLOCATION_MAX) with
increments of 10% (ALLOCATION_STEP) at each iteration. During each
iteration the test measures the actual memory bandwidth NUM_OF_RUNS times
to determine the impact of MBA on actual memory bandwidth.

After the MBA test completes all the memory bandwidth measurements are
parsed into an array. One array for resctrl Memory Bandwidth Monitoring
(MBM) measurements and one array for the Integrated Memory Controller
(iMC) measurements. Each array has a hardcoded size of 1024 that is
large enough to hold the current test data, but this hardcoded value makes
the implementation difficult to understand. It will not be clear that this
array needs to be reconsidered if any of the test parameters are changed.

Replace the magic constant as array size with the test parameters the
array size depends on.

Reported-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Closes: https://lore.kernel.org/all/45af2a8c-517d-8f0d-137d-ad0f3f6a3c68@linux.intel.com/
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
2024-11-04 17:02:03 -07:00
..

resctrl_tests - resctrl file system test suit

Authors:
	Fenghua Yu <fenghua.yu@intel.com>
	Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>,

resctrl_tests tests various resctrl functionalities and interfaces including
both software and hardware.

Currently it supports Memory Bandwidth Monitoring test and Memory Bandwidth
Allocation test on Intel RDT hardware. More tests will be added in the future.
And the test suit can be extended to cover AMD QoS and ARM MPAM hardware
as well.

resctrl_tests can be run with or without kselftest framework.

WITH KSELFTEST FRAMEWORK
=======================

BUILD
-----

Build executable file "resctrl_tests" from top level directory of the kernel source:
 $ make -C tools/testing/selftests TARGETS=resctrl

RUN
---

Run resctrl_tests as sudo or root since the test needs to mount resctrl file
system and change contents in the file system.
Using kselftest framework will run all supported tests within resctrl_tests:

 $ sudo make -C tools/testing/selftests TARGETS=resctrl run_tests

More details about kselftest framework can be found in
Documentation/dev-tools/kselftest.rst.

WITHOUT KSELFTEST FRAMEWORK
===========================

BUILD
-----

Build executable file "resctrl_tests" from this directory(tools/testing/selftests/resctrl/):
  $ make

RUN
---

Run resctrl_tests as sudo or root since the test needs to mount resctrl file
system and change contents in the file system.
Executing the test without any parameter will run all supported tests:

 $ sudo ./resctrl_tests

OVERVIEW OF EXECUTION
=====================

A test case has four stages:

  - setup: mount resctrl file system, create group, setup schemata, move test
    process pids to tasks, start benchmark.
  - execute: let benchmark run
  - verify: get resctrl data and verify the data with another source, e.g.
    perf event.
  - teardown: umount resctrl and clear temporary files.

ARGUMENTS
=========

Parameter '-h' shows usage information.

usage: resctrl_tests [-h] [-b "benchmark_cmd [options]"] [-t test list] [-n no_of_bits]
        -b benchmark_cmd [options]: run specified benchmark for MBM, MBA and CMT default benchmark is builtin fill_buf
        -t test list: run tests specified in the test list, e.g. -t mbm,mba,cmt,cat
        -n no_of_bits: run cache tests using specified no of bits in cache bit mask
        -p cpu_no: specify CPU number to run the test. 1 is default
        -h: help