RE: [PATCH v3 03/14] test/mcslock: scale test based on number of cores

Konstantin Ananyev
2026-01-22T10:41:09Z

> This test uses loops to synchronize but has problems on systems
> with high number of cores. Scale iterations to the number of
> cores.
>
> Fixes: 32dcb9fd2a22 ("test/mcslock: add MCS queued lock unit test")
> Cc: stable@dpdk.org
>
> Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
> ---
> app/test/test_mcslock.c | 10 +++++++---
> 1 file changed, 7 insertions(+), 3 deletions(-)
>
> diff --git a/app/test/test_mcslock.c b/app/test/test_mcslock.c
> index 245df99a5d..b182da72f1 100644
> --- a/app/test/test_mcslock.c
> +++ b/app/test/test_mcslock.c
> @@ -42,6 +42,10 @@ RTE_ATOMIC(rte_mcslock_t *) p_ml_perf;
>
> static unsigned int count;
>
> +#define MAX_LOOP_BASE 1000000u
> +#define MAX_LOOP_MIN 10000u
> +static unsigned int max_loop;
> +
> static RTE_ATOMIC(uint32_t) synchro;
>
> static int
> @@ -60,8 +64,6 @@ test_mcslock_per_core(__rte_unused void *arg)
>
> static uint64_t time_count[RTE_MAX_LCORE] = {0};
>
> -#define MAX_LOOP 1000000
> -
> static int
> load_loop_fn(void *func_param)
> {
> @@ -78,7 +80,7 @@ load_loop_fn(void *func_param)
> rte_wait_until_equal_32((uint32_t *)(uintptr_t)&synchro, 1,
> rte_memory_order_relaxed);
>
> begin = rte_get_timer_cycles();
> - while (lcount < MAX_LOOP) {
> + while (lcount < max_loop) {
> if (use_lock)
> rte_mcslock_lock(&p_ml_perf, &ml_perf_me);
>
> @@ -175,6 +177,8 @@ test_mcslock(void)
> rte_mcslock_t ml_me;
> rte_mcslock_t ml_try_me;
>
> + max_loop = test_scale_iterations(MAX_LOOP_BASE, MAX_LOOP_MIN);
> +

Here, and in other similar cases, would it make sense to terminate by timeout
(i.e. number of cycles passed since start of the test)?

> /*
> * Test mcs lock & unlock on each core
> */
> --
> 2.51.0