DPDK patches and discussions
 help / color / mirror / Atom feed
From: Andrew Rybchenko <arybchenko@solarflare.com>
To: Yongseok Koh <yskoh@mellanox.com>, <olivier.matz@6wind.com>,
	<shahafs@mellanox.com>
Cc: <dev@dpdk.org>, <roszenrami@gmail.com>, <david.marchand@redhat.com>
Subject: Re: [dpdk-dev] [PATCH v3 1/2] mbuf: add function returning default buffer address
Date: Fri, 11 Jan 2019 11:14:22 +0300
Message-ID: <2934bc73-98e6-643a-0d61-cf7804e1535d@solarflare.com> (raw)
In-Reply-To: <20190110183528.42503-1-yskoh@mellanox.com>

On 1/10/19 9:35 PM, Yongseok Koh wrote:
> This patch introduces two new functions - rte_mbuf_buf_addr() and
> rte_mbuf_data_addr_default().
>
> rte_mbuf_buf_addr() reutrns the default buffer address of given mbuf which
> comes after mbuf structure and private data.
>
> rte_mbuf_data_addr_default() returns the default address of mbuf data
> taking the headroom into account.
>
> Signed-off-by: Yongseok Koh <yskoh@mellanox.com>
> ---
>
> v3:
> * rename functions
>
> v2:
> * initial implementation
>
>   lib/librte_mbuf/rte_mbuf.h | 43 ++++++++++++++++++++++++++++++++++++++++---
>   1 file changed, 40 insertions(+), 3 deletions(-)
>
> diff --git a/lib/librte_mbuf/rte_mbuf.h b/lib/librte_mbuf/rte_mbuf.h
> index bc562dc8a9..486566fc28 100644
> --- a/lib/librte_mbuf/rte_mbuf.h
> +++ b/lib/librte_mbuf/rte_mbuf.h
> @@ -788,8 +788,47 @@ rte_mbuf_from_indirect(struct rte_mbuf *mi)
>   }
>   
>   /**
> + * Return the default buffer address of the mbuf.
> + *
> + * @param mb
> + *   The pointer to the mbuf.
> + * @param mp
> + *   The pointer to the mempool of the mbuf.
> + * @return
> + *   The pointer of the mbuf buffer.
> + */
> +static inline char * __rte_experimental
> +rte_mbuf_buf_addr(struct rte_mbuf *mb, struct rte_mempool *mp)

struct rte_mbuf has pool member. So, I don't understand why mp
argument is required. I guess there is a reason, but it should be
explained in comments. I see motivation in rte_mbuf_to_baddr()
description, but rte_mbuf_buf_add() does not explain it.

Also right now the function name looks like simple get accessor for
buf_addr and I'd expect to seem one line implementation may be
with extra debug checks: return mb->buf_addr.

May be rte_mbuf_direct_buf_addr() ?
If so, similar below rte_mbuf_direct_data_addr_default().

> +{
> +	char *buffer_addr;
> +
> +	buffer_addr = (char *)mb + sizeof(*mb) + rte_pktmbuf_priv_size(mp);
> +	return buffer_addr;
> +}
> +
> +
> +/**
> + * Return the default address of the beginning of the mbuf data.
> + *
> + * @param mb
> + *   The pointer to the mbuf.
> + * @return
> + *   The pointer of the beginning of the mbuf data.
> + */
> +static inline char * __rte_experimental
> +rte_mbuf_data_addr_default(struct rte_mbuf *mb)
> +{
> +	return rte_mbuf_buf_addr(mb, mb->pool) + RTE_PKTMBUF_HEADROOM;
> +}
> +
> +/**
>    * Return the buffer address embedded in the given mbuf.
>    *
> + * Note that accessing mempool pointer of a mbuf is expensive because the
> + * pointer is stored in the 2nd cache line of mbuf. If mempool is known, it
> + * is better not to reference the mempool pointer in mbuf but calling
> + * rte_mbuf_buf_addr() would be more efficient.
> + *
>    * @param md
>    *   The pointer to the mbuf.
>    * @return
> @@ -798,9 +837,7 @@ rte_mbuf_from_indirect(struct rte_mbuf *mi)
>   static inline char *
>   rte_mbuf_to_baddr(struct rte_mbuf *md)
>   {
> -	char *buffer_addr;
> -	buffer_addr = (char *)md + sizeof(*md) + rte_pktmbuf_priv_size(md->pool);
> -	return buffer_addr;
> +	return rte_mbuf_buf_addr(md, md->pool);
>   }
>   
>   /**

  parent reply	other threads:[~2019-01-11  8:14 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-01-09  8:54 [dpdk-dev] [PATCH] net/mlx5: fix instruction hotspot on replenishing Rx buffer Yongseok Koh
2019-01-09  9:38 ` David Marchand
2019-01-09  9:52   ` Olivier Matz
2019-01-09  9:56     ` Yongseok Koh
2019-01-09 10:05       ` David Marchand
2019-01-09 10:11         ` Yongseok Koh
2019-01-09 13:19 ` [dpdk-dev] [PATCH v2 1/2] mbuf: add function returning default buffer address Yongseok Koh
2019-01-09 13:19   ` [dpdk-dev] [PATCH v2 2/2] net/mlx5: fix instruction hotspot on replenishing Rx buffer Yongseok Koh
2019-01-09 13:46   ` [dpdk-dev] [PATCH v2 1/2] mbuf: add function returning default buffer address David Marchand
2019-01-10  1:39     ` Rami Rosen
2019-01-10 18:18       ` Yongseok Koh
2019-01-10 18:22     ` Yongseok Koh
2019-01-10 18:35 ` [dpdk-dev] [PATCH v3 " Yongseok Koh
2019-01-10 18:35   ` [dpdk-dev] [PATCH v3 2/2] net/mlx5: fix instruction hotspot on replenishing Rx buffer Yongseok Koh
2019-01-10 19:10     ` Shahaf Shuler
2019-01-11  8:14   ` Andrew Rybchenko [this message]
2019-01-11 11:03     ` [dpdk-dev] [PATCH v3 1/2] mbuf: add function returning default buffer address Yongseok Koh
2019-01-11 11:17       ` Andrew Rybchenko
2019-01-11 11:37         ` Yongseok Koh
2019-01-11 11:57         ` Bruce Richardson
2019-01-11 12:48           ` David Marchand
2019-01-14 15:51             ` Olivier Matz
2019-01-10 22:40 ` [dpdk-dev] [PATCH v4 " Yongseok Koh
2019-01-10 22:40   ` [dpdk-dev] [PATCH v4 2/2] net/mlx5: fix instruction hotspot on replenishing Rx buffer Yongseok Koh
2019-01-11  8:05   ` [dpdk-dev] [PATCH v4 1/2] mbuf: add function returning default buffer address Olivier Matz
2019-01-11  8:11   ` David Marchand
2019-01-11  8:32     ` David Marchand
2019-01-11 11:09       ` Yongseok Koh
2019-01-11 10:25     ` Thomas Monjalon
2019-01-14 21:16 ` [dpdk-dev] [PATCH v5 1/2] mbuf: add function returning " Yongseok Koh
2019-01-14 21:16   ` [dpdk-dev] [PATCH v5 2/2] net/mlx5: fix instruction hotspot on replenishing Rx buffer Yongseok Koh
2019-02-06 15:54     ` Kevin Traynor
2019-02-21 19:10       ` Kevin Traynor
2019-03-08  2:05         ` Yongseok Koh
2019-01-15  1:35   ` [dpdk-dev] [PATCH v5 1/2] mbuf: add function returning buffer address Thomas Monjalon

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=2934bc73-98e6-643a-0d61-cf7804e1535d@solarflare.com \
    --to=arybchenko@solarflare.com \
    --cc=david.marchand@redhat.com \
    --cc=dev@dpdk.org \
    --cc=olivier.matz@6wind.com \
    --cc=roszenrami@gmail.com \
    --cc=shahafs@mellanox.com \
    --cc=yskoh@mellanox.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

DPDK patches and discussions

This inbox may be cloned and mirrored by anyone:

	git clone --mirror https://inbox.dpdk.org/dev/0 dev/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 dev dev/ https://inbox.dpdk.org/dev \
		dev@dpdk.org
	public-inbox-index dev

Example config snippet for mirrors.
Newsgroup available over NNTP:
	nntp://inbox.dpdk.org/inbox.dpdk.dev


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git