[v4,00/16] selftests/resctrl: resctrl_val() related cleanups & improvements

Message

Ilpo Järvinen May 20, 2024, 12:30 p.m. UTC

Hi all,

This series does a number of cleanups into resctrl_val() and
generalizes it by removing test name specific handling from the
function.

One of the changes improves MBA/MBM measurement by narrowing down the
period the resctrl FS derived memory bandwidth numbers are measured
over. My feel is it didn't cause noticeable difference into the numbers
because they're generally good anyway except for the small number of
outliers. To see the impact on outliers, I'd need to setup a test to
run large number of replications and do a statistical analysis, which
I've not spent my time on. Even without the statistical analysis, the
new way to measure seems obviously better and makes sense even if I
cannot see a major improvement with the setup I'm using.

v4:
- Merged close fix into IMC READ+WRITE rework patch
- Add loop to reset imc_counters_config fds to -1 to be able know which
  need closing
- Introduce perf_close_imc_mem_bw() to close fds
- Open resctrl mem bw file (twice) beforehand to avoid opening it during
  the test
- Remove MBM .mongrp setup
- Remove mongrp from CMT test

v3:
- Rename init functions to <testname>_init()
- Replace for loops with READ+WRITE statements for clarity
- Don't drop Return: entry from perf_open_imc_mem_bw() func comment
- New patch: Fix closing of IMC fds in case of error
- New patch: Make "bandwidth" consistent in comments & prints
- New patch: Simplify mem bandwidth file code
- Remove wrong comment
- Changed grp_name check to return -1 on fail (internal sanity check)

v2:
- Resolved conflicts with kselftest/next
- Spaces -> tabs correction

Ilpo Järvinen (16):
  selftests/resctrl: Fix closing IMC fds on error and open-code R+W
    instead of loops
  selftests/resctrl: Calculate resctrl FS derived mem bw over sleep(1)
    only
  selftests/resctrl: Make "bandwidth" consistent in comments & prints
  selftests/resctrl: Consolidate get_domain_id() into resctrl_val()
  selftests/resctrl: Use correct type for pids
  selftests/resctrl: Cleanup bm_pid and ppid usage & limit scope
  selftests/resctrl: Rename measure_vals() to measure_mem_bw_vals() &
    document
  selftests/resctrl: Simplify mem bandwidth file code for MBA & MBM
    tests
  selftests/resctrl: Add ->measure() callback to resctrl_val_param
  selftests/resctrl: Add ->init() callback into resctrl_val_param
  selftests/resctrl: Simplify bandwidth report type handling
  selftests/resctrl: Make some strings passed to resctrlfs functions
    const
  selftests/resctrl: Convert ctrlgrp & mongrp to pointers
  selftests/resctrl: Remove mongrp from MBA test
  selftests/resctrl: Remove mongrp from CMT test
  selftests/resctrl: Remove test name comparing from
    write_bm_pid_to_resctrl()

 tools/testing/selftests/resctrl/cache.c       |   6 +-
 tools/testing/selftests/resctrl/cat_test.c    |   5 +-
 tools/testing/selftests/resctrl/cmt_test.c    |  22 +-
 tools/testing/selftests/resctrl/mba_test.c    |  26 +-
 tools/testing/selftests/resctrl/mbm_test.c    |  26 +-
 tools/testing/selftests/resctrl/resctrl.h     |  49 ++-
 tools/testing/selftests/resctrl/resctrl_val.c | 362 ++++++++----------
 tools/testing/selftests/resctrl/resctrlfs.c   |  64 ++--
 8 files changed, 287 insertions(+), 273 deletions(-)