From: Jerin Jacob <jerin.jacob@caviumnetworks.com>
To: Kiran Kumar <kkokkilagadda@caviumnetworks.com>
Cc: dev@dpdk.org, maciej.czekaj@caviumnetworks.com
Subject: Re: [dpdk-dev] [PATCH] net/thunderx: Block sq door writes on zero pkts
Date: Wed, 11 Jul 2018 13:07:54 +0530 [thread overview]
Message-ID: <20180711073752.GA23709@jerin> (raw)
In-Reply-To: <1531293723-930-1-git-send-email-kkokkilagadda@caviumnetworks.com>
-----Original Message-----
> Date: Wed, 11 Jul 2018 12:52:03 +0530
> From: Kiran Kumar <kkokkilagadda@caviumnetworks.com>
> To: dev@dpdk.org
> Cc: jerin.jacob@caviumnetworks.com, maciej.czekaj@caviumnetworks.com, Kiran
> Kumar <kkokkilagadda@caviumnetworks.com>
> Subject: [dpdk-dev] [PATCH] net/thunderx: Block sq door writes on zero pkts
> X-Mailer: git-send-email 2.7.4
Use small letter to start the comment.(s/Block/block)
I think, we can change the subject to "avoid sq door bell writes on zero packet"
>
> With current code, we are performing sq door writes even with 0 pkts.
> this will create pressure on register bus. This patch will block these
> writes.
Could rename to:
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")
add
Cc: stable@dpdk.org
>
> Signed-off-by: Kiran Kumar <kkokkilagadda@caviumnetworks.com>
> ---
> drivers/net/thunderx/nicvf_rxtx.c | 12 +++++++-----
> 1 file changed, 7 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/net/thunderx/nicvf_rxtx.c b/drivers/net/thunderx/nicvf_rxtx.c
> index 72305d9..8075a8e 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);
> + }
Please add same logic for nicvf_xmit_pkts_multiseg function.
With above changes:
Acked-by: Jerin Jacob <jerin.jacob@caviumnetworks.com>
> return i;
> }
>
> --
> 2.7.4
>
next prev parent reply other threads:[~2018-07-11 7:38 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-11 7:22 Kiran Kumar
2018-07-11 7:37 ` Jerin Jacob [this message]
2018-07-11 8:24 ` [dpdk-dev] [PATCH v2] net/thunderx: avoid sq door bell writes on zero packets Kiran Kumar
2018-07-11 9:05 ` Jerin Jacob
2018-07-18 9:41 ` Ferruh Yigit
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