Re: [PATCH v1 3/3] examples/l3fwd-power: enable PMD power mgmt on Arm

["Hunt, David" <david.hunt@intel.com>]

On 25/08/2022 07:42, Feifei Wang wrote:
> For Arm aarch, power monitor uses WFE instruction to enable, which can
> not exit automatically within the time limit. This means
> 'rte_power_monitor_wakeup' API needs to be called to wake up sleep cores
> if there is no store operation to monitored address.
>
> Furthermore, we disable power monitor feature on the main core so that it
> can be used to wake up other sleeping cores when it receives SIGINT
> siginal.
>
> Signed-off-by: Feifei Wang <feifei.wang2@arm.com>
> Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
> ---
>   examples/l3fwd-power/main.c | 30 +++++++++++++++++++++++++++++-
>   1 file changed, 29 insertions(+), 1 deletion(-)
>
> diff --git a/examples/l3fwd-power/main.c b/examples/l3fwd-power/main.c
> index 887c6eae3f..2bd0d700f0 100644
> --- a/examples/l3fwd-power/main.c
> +++ b/examples/l3fwd-power/main.c
> @@ -432,8 +432,16 @@ static void
>   signal_exit_now(int sigtype)
>   {
>   
> -	if (sigtype == SIGINT)
> +	if (sigtype == SIGINT) {
> +#if defined(RTE_ARCH_ARM64)
> +	/**
> +	 * wake_up api does not need input parameter on Arm,
> +	 * so 0 is meaningless here.
> +	 */
> +		rte_power_monitor_wakeup(0);
> +#endif
>   		quit_signal = true;
> +	}
>   
>   }
>   
> @@ -2885,6 +2893,25 @@ main(int argc, char **argv)
>   						"Error setting scaling freq max: err=%d, lcore %d\n",
>   							ret, lcore_id);
>   
> +#if defined(RTE_ARCH_ARM64)
> +				/* Ensure the main lcore does not enter the power-monitor state,
> +				 * so that it can be used to wake up other lcores on ARM.
> +				 * This is due to WFE instruction has no timeout wake-up mechanism,
> +				 * and if users want to exit actively, the main lcore is needed
> +				 * to send SEV instruction to wake up other lcores.
> +				 */
> +				unsigned int main_lcore = rte_get_main_lcore();
> +				if (lcore_id != main_lcore ||
> +						pmgmt_type != RTE_POWER_MGMT_TYPE_MONITOR) {
> +					ret = rte_power_ethdev_pmgmt_queue_enable(
> +							lcore_id, portid, queueid,
> +							pmgmt_type);
> +					if (ret < 0)
> +						rte_exit(EXIT_FAILURE,
> +							"rte_power_ethdev_pmgmt_queue_enable: err=%d, port=%d\n",
> +							ret, portid);
> +				}
> +#else
>   				ret = rte_power_ethdev_pmgmt_queue_enable(
>   						lcore_id, portid, queueid,
>   						pmgmt_type);
> @@ -2892,6 +2919,7 @@ main(int argc, char **argv)
>   					rte_exit(EXIT_FAILURE,
>   						"rte_power_ethdev_pmgmt_queue_enable: err=%d, port=%d\n",
>   							ret, portid);
> +#endif
>   			}
>   		}
>   	}


Hi Feifei,

Acked-by: David Hunt <david.hunt@intel.com>