[dpdk-dev] [PATCH] service: add new `rte_service_lcore_count_services` API

[Van Haaren, Harry]

> From: Pavan Nikhilesh [mailto:pbhagavatula at caviumnetworks.com]
> Sent: Wednesday, August 23, 2017 12:17 PM
> To: Van Haaren, Harry <harry.van.haaren at intel.com>
> Cc: dev at dpdk.org; Pavan Nikhilesh <pbhagavatula at caviumnetworks.com>
> Subject: [dpdk-dev] [PATCH] service: add new `rte_service_lcore_count_services` API
> 
> This new API returns the number of services that are running on a specific
> service core. It allows an application to decide which service core to run
> a new service on.
> 
> Signed-off-by: Pavan Nikhilesh <pbhagavatula at caviumnetworks.com>

Hi,

Thanks - yes a useful addition to the API. Comments inline below, apart from that, thanks for the addition!

-H

> ---
>  lib/librte_eal/common/include/rte_service.h | 12 ++++++++++++
>  lib/librte_eal/common/rte_service.c         | 11 +++++++++++
>  2 files changed, 23 insertions(+)
> 
> diff --git a/lib/librte_eal/common/include/rte_service.h
> b/lib/librte_eal/common/include/rte_service.h
> index 7c6f738..5f0904f 100644
> --- a/lib/librte_eal/common/include/rte_service.h
> +++ b/lib/librte_eal/common/include/rte_service.h
> @@ -374,6 +374,18 @@ int32_t rte_service_lcore_list(uint32_t array[], uint32_t n);
>   * @warning
>   * @b EXPERIMENTAL: this API may change without prior notice
>   *
> + * Get the numer of services running on the supplied lcore.
> + *
> + * @param Lcore Id of the service core.
> + * @retval >=0 Number of services registered to this core.
> + * @retval -EINVAL The provided lcore is not a service core.
> + */
> +int32_t rte_service_lcore_count_services(uint32_t lcore);

Perhaps -ENOTSUP would be clearer for "not a service core"?
Then -EINVAL becomes available to indicate an invalid lcore-id pass in?

> +
> +/**
> + * @warning
> + * @b EXPERIMENTAL: this API may change without prior notice
> + *
>   * Dumps any information available about the service. If service is NULL,
>   * dumps info for all services.
>   */
> diff --git a/lib/librte_eal/common/rte_service.c b/lib/librte_eal/common/rte_service.c
> index 7efb76d..ddaed22 100644
> --- a/lib/librte_eal/common/rte_service.c
> +++ b/lib/librte_eal/common/rte_service.c
> @@ -397,6 +397,17 @@ rte_service_lcore_list(uint32_t array[], uint32_t n)
>  }
> 
>  int32_t
> +rte_service_lcore_count_services(uint32_t lcore)
> +{

/* need to error check lcore here, return -EINVAL if not valid. */

> +	struct core_state *cs = &lcore_states[lcore];
> +
> +	if (!cs->is_service_core)
> +		return -EINVAL;

/* suggesting to use -ENOTSUP instead here */

> +
> +	return __builtin_popcountll(cs->service_mask);
> +}
> +
> +int32_t
>  rte_service_start_with_defaults(void)
>  {
>  	/* create a default mapping from cores to services, then start the
> --
> 2.7.4