Re: [dpdk-dev] [RFC PATCH] Adding RTE_KNI_PREEMPT configuration option

[Marc Sune <marc.sune@bisdn.de>]

Hi guys,

Any comment, suggestion or objection to this patch? Otherwise I would 
send a non-RFC patch

Thanks
Marc

On 05/11/14 01:17, Marc Sune wrote:
> This patch introduces CONFIG_RTE_KNI_PREEMPT flag. When set to 'no', KNI
> kernel thread(s) do not call schedule_timeout_interruptible(), which improves
> overall KNI performance at the expense of CPU cycles (polling).
>
> Default values is 'yes', maintaining the same behaviour as of now.
>
> Note: this RFC patch is based on v1.7.1, since I was using a 1.7 application.
> It will eventually be rebased to 1.8 upon acceptance.
>
> Signed-off-by: Marc Sune <marc.sune@bisdn.de>
> ---
>   config/common_linuxapp                 |    1 +
>   lib/librte_eal/linuxapp/kni/kni_misc.c |    4 ++++
>   2 files changed, 5 insertions(+)
>
> diff --git a/config/common_linuxapp b/config/common_linuxapp
> index 9047975..9cebcf1 100644
> --- a/config/common_linuxapp
> +++ b/config/common_linuxapp
> @@ -382,6 +382,7 @@ CONFIG_RTE_LIBRTE_PIPELINE=y
>   # Compile librte_kni
>   #
>   CONFIG_RTE_LIBRTE_KNI=y
> +CONFIG_RTE_KNI_PREEMPT=y
>   CONFIG_RTE_KNI_KO_DEBUG=n
>   CONFIG_RTE_KNI_VHOST=n
>   CONFIG_RTE_KNI_VHOST_MAX_CACHE_SIZE=1024
> diff --git a/lib/librte_eal/linuxapp/kni/kni_misc.c b/lib/librte_eal/linuxapp/kni/kni_misc.c
> index ba77776..e7e6c27 100644
> --- a/lib/librte_eal/linuxapp/kni/kni_misc.c
> +++ b/lib/librte_eal/linuxapp/kni/kni_misc.c
> @@ -229,9 +229,11 @@ kni_thread_single(void *unused)
>   			}
>   		}
>   		up_read(&kni_list_lock);
> +#ifdef RTE_KNI_PREEMPT
>   		/* reschedule out for a while */
>   		schedule_timeout_interruptible(usecs_to_jiffies( \
>   				KNI_KTHREAD_RESCHEDULE_INTERVAL));
> +#endif
>   	}
>   
>   	return 0;
> @@ -252,8 +254,10 @@ kni_thread_multiple(void *param)
>   #endif
>   			kni_net_poll_resp(dev);
>   		}
> +#ifdef RTE_KNI_PREEMPT
>   		schedule_timeout_interruptible(usecs_to_jiffies( \
>   				KNI_KTHREAD_RESCHEDULE_INTERVAL));
> +#endif
>   	}
>   
>   	return 0;