> wrk_cmd variable is used to signal the worker thread to start
> or stop the stress test loop. Relaxed barriers are used
> to achieve the same.
>
> Signed-off-by: Honnappa Nagarahalli <honnappa.nagaraha...@arm.com>
> Reviewed-by: Ola Liljedahl <ola.liljed...@arm.com>
> Reviewed-by: Feifei Wang <feifei.w...@arm.com>
> ---
> app/test/test_ring_stress_impl.h | 18 +++++++++---------
> 1 file changed, 9 insertions(+), 9 deletions(-)
>
> diff --git a/app/test/test_ring_stress_impl.h
> b/app/test/test_ring_stress_impl.h
> index f9ca63b908..ee8293bb04 100644
> --- a/app/test/test_ring_stress_impl.h
> +++ b/app/test/test_ring_stress_impl.h
> @@ -22,7 +22,7 @@ enum {
> WRK_CMD_RUN,
> };
>
> -static volatile uint32_t wrk_cmd __rte_cache_aligned;
> +static volatile uint32_t wrk_cmd __rte_cache_aligned = WRK_CMD_STOP;
If we switch to using atomic load/store for 'wrk_cmd',
then we can get remove 'volatile' classifier in the 'wrk_cmd' definition above?
>
> /* test run-time in seconds */
> static const uint32_t run_time = 60;
> @@ -197,10 +197,12 @@ test_worker(void *arg, const char *fname, int32_t prcs)
> fill_ring_elm(&def_elm, UINT32_MAX);
> fill_ring_elm(&loc_elm, lc);
>
> - while (wrk_cmd != WRK_CMD_RUN) {
> - rte_smp_rmb();
> + /* Acquire ordering is not required as the main is not
> + * really releasing any data through 'wrk_cmd' to
> + * the worker.
> + */
> + while (__atomic_load_n(&wrk_cmd, __ATOMIC_RELAXED) != WRK_CMD_RUN)
> rte_pause();
> - }
>
> cl = rte_rdtsc_precise();
>
> @@ -242,7 +244,7 @@ test_worker(void *arg, const char *fname, int32_t prcs)
>
> lcore_stat_update(&la->stats, 1, num, tm0 + tm1, prcs);
>
> - } while (wrk_cmd == WRK_CMD_RUN);
> + } while (__atomic_load_n(&wrk_cmd, __ATOMIC_RELAXED) == WRK_CMD_RUN);
>
> cl = rte_rdtsc_precise() - cl;
> if (prcs == 0)
> @@ -356,14 +358,12 @@ test_mt1(int (*test)(void *))
> }
>
> /* signal worker to start test */
> - wrk_cmd = WRK_CMD_RUN;
> - rte_smp_wmb();
> + __atomic_store_n(&wrk_cmd, WRK_CMD_RUN, __ATOMIC_RELEASE);
>
> usleep(run_time * US_PER_S);
>
> /* signal worker to start test */
> - wrk_cmd = WRK_CMD_STOP;
> - rte_smp_wmb();
> + __atomic_store_n(&wrk_cmd, WRK_CMD_STOP, __ATOMIC_RELEASE);
>
> /* wait for workers and collect stats. */
> mc = rte_lcore_id();
> --
> 2.25.1
