diff options
| author | Reinette Chatre <reinette.chatre@intel.com> | 2024-10-24 14:18:43 -0700 |
|---|---|---|
| committer | Shuah Khan <skhan@linuxfoundation.org> | 2024-11-04 17:02:02 -0700 |
| commit | efffa8c40166af680959c030a815afa8d06af66a (patch) | |
| tree | b0c8c70bc3e873591ddc33a1c41c850ed1d95c05 | |
| parent | 46058430fc5d39c114f7e1b9c6ff14c9f41bd531 (diff) | |
selftests/resctrl: Make wraparound handling obvious
Within mba_setup() the programmed bandwidth delay value starts
at the maximum (100, or rather ALLOCATION_MAX) and progresses
towards ALLOCATION_MIN by decrementing with ALLOCATION_STEP.
The programmed bandwidth delay should never be negative, so
representing it with an unsigned int is most appropriate. This
may introduce confusion because of the "allocation > ALLOCATION_MAX"
check used to check wraparound of the subtraction.
Modify the mba_setup() flow to start at the minimum, ALLOCATION_MIN,
and incrementally, with ALLOCATION_STEP steps, adjust the
bandwidth delay value. This avoids wraparound while making the purpose
of "allocation > ALLOCATION_MAX" clear and eliminates the
need for the "allocation < ALLOCATION_MIN" check.
Reported-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Closes: https://lore.kernel.org/lkml/1903ac13-5c9c-ef8d-78e0-417ac34a971b@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>
| -rw-r--r-- | tools/testing/selftests/resctrl/mba_test.c | 12 |
1 files changed, 7 insertions, 5 deletions
diff --git a/tools/testing/selftests/resctrl/mba_test.c b/tools/testing/selftests/resctrl/mba_test.c index ab8496a4925b..da40a8ed4413 100644 --- a/tools/testing/selftests/resctrl/mba_test.c +++ b/tools/testing/selftests/resctrl/mba_test.c @@ -39,7 +39,8 @@ static int mba_setup(const struct resctrl_test *test, const struct user_params *uparams, struct resctrl_val_param *p) { - static int runs_per_allocation, allocation = 100; + static unsigned int allocation = ALLOCATION_MIN; + static int runs_per_allocation; char allocation_str[64]; int ret; @@ -50,7 +51,7 @@ static int mba_setup(const struct resctrl_test *test, if (runs_per_allocation++ != 0) return 0; - if (allocation < ALLOCATION_MIN || allocation > ALLOCATION_MAX) + if (allocation > ALLOCATION_MAX) return END_OF_TESTS; sprintf(allocation_str, "%d", allocation); @@ -59,7 +60,7 @@ static int mba_setup(const struct resctrl_test *test, if (ret < 0) return ret; - allocation -= ALLOCATION_STEP; + allocation += ALLOCATION_STEP; return 0; } @@ -72,8 +73,9 @@ static int mba_measure(const struct user_params *uparams, static bool show_mba_info(unsigned long *bw_imc, unsigned long *bw_resc) { - int allocation, runs; + unsigned int allocation; bool ret = false; + int runs; ksft_print_msg("Results are displayed in (MB)\n"); /* Memory bandwidth from 100% down to 10% */ @@ -103,7 +105,7 @@ static bool show_mba_info(unsigned long *bw_imc, unsigned long *bw_resc) avg_diff_per > MAX_DIFF_PERCENT ? "Fail:" : "Pass:", MAX_DIFF_PERCENT, - ALLOCATION_MAX - ALLOCATION_STEP * allocation); + ALLOCATION_MIN + ALLOCATION_STEP * allocation); ksft_print_msg("avg_diff_per: %d%%\n", avg_diff_per); ksft_print_msg("avg_bw_imc: %lu\n", avg_bw_imc); |