From: Jerin Jacob <jerin.jacob@caviumnetworks.com>
To: Kiran Kumar <kkokkilagadda@caviumnetworks.com>
Cc: maciej.czekaj@caviumnetworks.com, ferruh.yigit@intel.com,
dev@dpdk.org, stable@dpdk.org
Subject: Re: [dpdk-stable] [dpdk-dev] [PATCH v2] net/thunderx: avoid sq door bell writes on zero packets
Date: Wed, 11 Jul 2018 14:35:59 +0530 [thread overview]
Message-ID: <20180711090557.GA22077@jerin> (raw)
In-Reply-To: <1531297476-4604-1-git-send-email-kkokkilagadda@caviumnetworks.com>
-----Original Message-----
> Date: Wed, 11 Jul 2018 13:54:36 +0530
> From: Kiran Kumar <kkokkilagadda@caviumnetworks.com>
> To: jerin.jacob@caviumnetworks.com, maciej.czekaj@caviumnetworks.com,
> ferruh.yigit@intel.com
> Cc: dev@dpdk.org, Kiran Kumar <kkokkilagadda@caviumnetworks.com>,
> stable@dpdk.org
> Subject: [dpdk-dev] [PATCH v2] net/thunderx: avoid sq door bell writes on
> zero packets
> X-Mailer: git-send-email 2.7.4
>
> Avoid sq door bell write on zero packet case to reduce additional
> traffic on register bus.
>
> Fixes: 1c421f18e0 ("net/thunderx: add single and multi-segment Tx")
> Cc: stable@dpdk.org
>
> Signed-off-by: Kiran Kumar <kkokkilagadda@caviumnetworks.com>
Acked-by: Jerin Jacob <jerin.jacob@caviumnetworks.com>
> ---
> v2 Changes:
> - changed summery and description.
> - added same optimization to nicvf_xmit_pkts_multiseg
>
> drivers/net/thunderx/nicvf_rxtx.c | 24 ++++++++++++++----------
> 1 file changed, 14 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/net/thunderx/nicvf_rxtx.c b/drivers/net/thunderx/nicvf_rxtx.c
> index 72305d9..6e075e2 100644
> --- a/drivers/net/thunderx/nicvf_rxtx.c
> +++ b/drivers/net/thunderx/nicvf_rxtx.c
> @@ -162,12 +162,14 @@ nicvf_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts, uint16_t nb_pkts)
> free_desc -= TX_DESC_PER_PKT;
> }
>
> - sq->tail = tail;
> - sq->xmit_bufs += i;
> - rte_wmb();
> + if (likely(i)) {
> + sq->tail = tail;
> + sq->xmit_bufs += i;
> + rte_wmb();
>
> - /* Inform HW to xmit the packets */
> - nicvf_addr_write(sq->sq_door, i * TX_DESC_PER_PKT);
> + /* Inform HW to xmit the packets */
> + nicvf_addr_write(sq->sq_door, i * TX_DESC_PER_PKT);
> + }
> return i;
> }
>
> @@ -218,12 +220,14 @@ nicvf_xmit_pkts_multiseg(void *tx_queue, struct rte_mbuf **tx_pkts,
> }
> }
>
> - sq->tail = tail;
> - sq->xmit_bufs += used_bufs;
> - rte_wmb();
> + if (likely(used_desc)) {
> + sq->tail = tail;
> + sq->xmit_bufs += used_bufs;
> + rte_wmb();
>
> - /* Inform HW to xmit the packets */
> - nicvf_addr_write(sq->sq_door, used_desc);
> + /* Inform HW to xmit the packets */
> + nicvf_addr_write(sq->sq_door, used_desc);
> + }
> return i;
> }
>
> --
> 2.7.4
>
next prev parent reply other threads:[~2018-07-11 9:06 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1531293723-930-1-git-send-email-kkokkilagadda@caviumnetworks.com>
2018-07-11 8:24 ` Kiran Kumar
2018-07-11 9:05 ` Jerin Jacob [this message]
2018-07-18 9:41 ` Ferruh Yigit
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