Re: [dpdk-dev] [PATCH v3] eal: restrict cores detection

[Thomas Monjalon <thomas.monjalon@6wind.com>]

2016-09-01 01:31, Jianfeng Tan:
> This patch uses pthread_getaffinity_np() to narrow down detected
> cores before parsing coremask (-c), corelist (-l), and coremap
> (--lcores).
> 
> The purpose of this patch is to leave out these core related options
> when DPDK applications are deployed under container env, so that
> users only specify core restriction as starting the instance.
[...]
> --- a/lib/librte_eal/common/eal_common_lcore.c
> +++ b/lib/librte_eal/common/eal_common_lcore.c
> @@ -57,6 +57,12 @@ rte_eal_cpu_init(void)
>  	struct rte_config *config = rte_eal_get_configuration();
>  	unsigned lcore_id;
>  	unsigned count = 0;
> +	rte_cpuset_t affinity_set;
> +	pthread_t tid = pthread_self();
> +

A comment is needed here to explain which errors we are checking.

> +	if (pthread_getaffinity_np(tid, sizeof(rte_cpuset_t),
> +				   &affinity_set) < 0)
> +		CPU_ZERO(&affinity_set);
>  
>  	/*
>  	 * Parse the maximum set of logical cores, detect the subset of running
> @@ -70,7 +76,8 @@ rte_eal_cpu_init(void)
>  
>  		/* in 1:1 mapping, record related cpu detected state */
>  		lcore_config[lcore_id].detected = eal_cpu_detected(lcore_id);
> -		if (lcore_config[lcore_id].detected == 0) {
> +		if (lcore_config[lcore_id].detected == 0 ||
> +		    !CPU_ISSET(lcore_id, &affinity_set)) {
>  			config->lcore_role[lcore_id] = ROLE_OFF;
>  			lcore_config[lcore_id].core_index = -1;
>  			continue;
>