Re: [dpdk-stable] [dpdk-dev] [PATCH v1 1/2] test/rwlock: add perf test case

["Ananyev, Konstantin" <konstantin.ananyev@intel.com>]

Hi,

> 
> Add performance test on all available cores to benchmark
> the scaling up performance and fairness of rw_lock.
> 
> Fixes: af75078faf ("first public release")
> Cc: stable@dpdk.org
> 
> Suggested-by: Gavin Hu <gavin.hu@arm.com>
> Signed-off-by: Joyce Kong <joyce.kong@arm.com>
> Reviewed-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
> Reviewed-by: Ola Liljedahl <ola.liljedahl@arm.com>
> Reviewed-by: Gavin Hu <gavin.hu@arm.com>
> Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
> ---
>  test/test/test_rwlock.c | 71 +++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 71 insertions(+)
> 
> diff --git a/test/test/test_rwlock.c b/test/test/test_rwlock.c
> index 29171c4..4766c09 100644
> --- a/test/test/test_rwlock.c
> +++ b/test/test/test_rwlock.c
> @@ -4,6 +4,7 @@
> 
>  #include <stdio.h>
>  #include <stdint.h>
> +#include <inttypes.h>
>  #include <unistd.h>
>  #include <sys/queue.h>
> 
> @@ -44,6 +45,7 @@
> 
>  static rte_rwlock_t sl;
>  static rte_rwlock_t sl_tab[RTE_MAX_LCORE];
> +static rte_atomic32_t synchro;
> 
>  static int
>  test_rwlock_per_core(__attribute__((unused)) void *arg)
> @@ -65,6 +67,72 @@ test_rwlock_per_core(__attribute__((unused)) void *arg)
>  	return 0;
>  }
> 
> +static rte_rwlock_t lk = RTE_RWLOCK_INITIALIZER;
> +static uint64_t lock_count[RTE_MAX_LCORE] = {0};
> +
> +#define TIME_MS 100
> +
> +static int
> +load_loop_fn(__attribute__((unused)) void *arg)
> +{
> +	uint64_t time_diff = 0, begin;
> +	uint64_t hz = rte_get_timer_hz();
> +	uint64_t lcount = 0;
> +	const unsigned int lcore = rte_lcore_id();
> +
> +	/* wait synchro for slaves */
> +	if (lcore != rte_get_master_lcore())
> +		while (rte_atomic32_read(&synchro) == 0)
> +			;
> +
> +	begin = rte_rdtsc_precise();
> +	while (time_diff < hz * TIME_MS / 1000) {
> +		rte_rwlock_write_lock(&lk);
> +		rte_pause();

Wouldn't it be more realistic to write/read some shared data here?
Again extra checking could be done in that case that lock behaves as expected.

> +		rte_rwlock_write_unlock(&lk);
> +		rte_rwlock_read_lock(&lk);
> +		rte_rwlock_read_lock(&lk);

Wonder what is the point of double rdlock here?
Konstantin

> +		rte_pause();
> +		rte_rwlock_read_unlock(&lk);
> +		rte_rwlock_read_unlock(&lk);
> +		lcount++;
> +		/* delay to make lock duty cycle slightly realistic */
> +		rte_pause();
> +		time_diff = rte_rdtsc_precise() - begin;
> +	}
> +	lock_count[lcore] = lcount;
> +	return 0;
> +}
> +