RE: [PATCH 2/2] net: thunderx: Enable CQE count threshold interrupt

[Pavel Fedin]

 Hello!

> -----Original Message-----
> From: netdev-owner@xxxxxxxxxxxxxxx [mailto:netdev-owner@xxxxxxxxxxxxxxx] On Behalf Of Sunil
> Goutham
> Sent: Wednesday, December 09, 2015 2:38 PM
> To: netdev@xxxxxxxxxxxxxxx
> Cc: linux-kernel@xxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; p.fedin@xxxxxxxxxxx;
> Sunil.Goutham@xxxxxxxxxxxxxxxxxx; Sunil Goutham
> Subject: [PATCH 2/2] net: thunderx: Enable CQE count threshold interrupt
> 
> From: Sunil Goutham <sgoutham@xxxxxxxxxx>
> 
> This feature is introduced in pass-2 chip and with this CQ interrupt
> coalescing will work based on both timer and count.
> 
> Signed-off-by: Sunil Goutham <sgoutham@xxxxxxxxxx>
> ---
>  drivers/net/ethernet/cavium/thunder/nic.h          |    2 ++
>  drivers/net/ethernet/cavium/thunder/nicvf_main.c   |    2 +-
>  drivers/net/ethernet/cavium/thunder/nicvf_queues.c |    5 ++++-
>  drivers/net/ethernet/cavium/thunder/nicvf_queues.h |    3 ++-
>  4 files changed, 9 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/net/ethernet/cavium/thunder/nic.h
> b/drivers/net/ethernet/cavium/thunder/nic.h
> index 02571f4..e782856 100644
> --- a/drivers/net/ethernet/cavium/thunder/nic.h
> +++ b/drivers/net/ethernet/cavium/thunder/nic.h
> @@ -34,6 +34,8 @@
>  /* NIC priv flags */
>  #define	NIC_SRIOV_ENABLED		BIT(0)
> 
> +#define	VNIC_NAPI_WEIGHT		NAPI_POLL_WEIGHT
> +
>  /* Min/Max packet size */
>  #define	NIC_HW_MIN_FRS			64
>  #define	NIC_HW_MAX_FRS			9200 /* 9216 max packet including FCS */
> diff --git a/drivers/net/ethernet/cavium/thunder/nicvf_main.c
> b/drivers/net/ethernet/cavium/thunder/nicvf_main.c
> index c24cb2a..e06a7f8 100644
> --- a/drivers/net/ethernet/cavium/thunder/nicvf_main.c
> +++ b/drivers/net/ethernet/cavium/thunder/nicvf_main.c
> @@ -1155,7 +1155,7 @@ int nicvf_open(struct net_device *netdev)
>  		cq_poll->cq_idx = qidx;
>  		cq_poll->nicvf = nic;
>  		netif_napi_add(netdev, &cq_poll->napi, nicvf_poll,
> -			       NAPI_POLL_WEIGHT);
> +			       VNIC_NAPI_WEIGHT);

 What's the sense in introducing another constant which is aliased to the previous one? Making LOC bigger?

>  		napi_enable(&cq_poll->napi);
>  		nic->napi[qidx] = cq_poll;
>  	}
> diff --git a/drivers/net/ethernet/cavium/thunder/nicvf_queues.c
> b/drivers/net/ethernet/cavium/thunder/nicvf_queues.c
> index b11fc09..4e9709e 100644
> --- a/drivers/net/ethernet/cavium/thunder/nicvf_queues.c
> +++ b/drivers/net/ethernet/cavium/thunder/nicvf_queues.c
> @@ -299,7 +299,10 @@ static int nicvf_init_cmp_queue(struct nicvf *nic,
>  		return err;
> 
>  	cq->desc = cq->dmem.base;
> -	cq->thresh = CMP_QUEUE_CQE_THRESH;
> +	if (!pass1_silicon(nic->pdev))
> +		cq->thresh = CMP_QUEUE_CQE_THRESH;
> +	else
> +		cq->thresh = 0;

 IMHO "cq->thresh = pass1_silicon(nic->pdev) ? CMP_QUEUE_CQE_THRESH : 0" looks less bulky.

>  	nic->cq_coalesce_usecs = (CMP_QUEUE_TIMER_THRESH * 0.05) - 1;
> 
>  	return 0;
> diff --git a/drivers/net/ethernet/cavium/thunder/nicvf_queues.h
> b/drivers/net/ethernet/cavium/thunder/nicvf_queues.h
> index a4f6667..0fae6ad 100644
> --- a/drivers/net/ethernet/cavium/thunder/nicvf_queues.h
> +++ b/drivers/net/ethernet/cavium/thunder/nicvf_queues.h
> @@ -10,6 +10,7 @@
>  #define NICVF_QUEUES_H
> 
>  #include <linux/netdevice.h>
> +#include "nic.h"
>  #include "q_struct.h"
> 
>  #define MAX_QUEUE_SET			128
> @@ -75,7 +76,7 @@
>   */
>  #define CMP_QSIZE		CMP_QUEUE_SIZE2
>  #define CMP_QUEUE_LEN		(1ULL << (CMP_QSIZE + 10))
> -#define CMP_QUEUE_CQE_THRESH	0
> +#define CMP_QUEUE_CQE_THRESH	(VNIC_NAPI_WEIGHT / 2)
>  #define CMP_QUEUE_TIMER_THRESH	80 /* ~2usec */
> 
>  #define RBDR_SIZE		RBDR_SIZE0
> --
> 1.7.1

Kind regards,
Pavel Fedin
Expert Engineer
Samsung Electronics Research center Russia


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