From: Olivier MATZ <olivier.matz@6wind.com>
To: Bruce Richardson <bruce.richardson@intel.com>, dev@dpdk.org
Subject: Re: [dpdk-dev] [PATCH 01/13] mbuf: replace data pointer by an offset
Date: Mon, 08 Sep 2014 11:52:31 +0200 [thread overview]
Message-ID: <540D7C5F.8000406@6wind.com> (raw)
In-Reply-To: <1409759378-10113-2-git-send-email-bruce.richardson@intel.com>
Hi Bruce,
On 09/03/2014 05:49 PM, Bruce Richardson wrote:
> From: Olivier Matz <olivier.matz@6wind.com>
>
> Original patch:
> The mbuf structure already contains a pointer to the beginning of the
> buffer (m->buf_addr). It is not needed to use 8 bytes again to store
> another pointer to the beginning of the data.
>
> Using a 16 bits unsigned integer is enough as we know that a mbuf is
> never longer than 64KB. We gain 6 bytes in the structure thanks to
> this modification.
>
> Signed-off-by: Olivier Matz <olivier.matz@6wind.com>
>
> This version:
> * Updated original patch to apply to latest on mainline.
> * Disabled vector PMD in config as it relies heavily on the mbuf layout
> This will be re-enabled in a subsequent commit once vPMD has been
> reworked to take account of mbuf changes.
>
> Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
>
> [...]
>
> diff --git a/lib/librte_mbuf/rte_mbuf.h b/lib/librte_mbuf/rte_mbuf.h
> index 32e8474..669e7f5 100644
> --- a/lib/librte_mbuf/rte_mbuf.h
> +++ b/lib/librte_mbuf/rte_mbuf.h
> @@ -119,6 +119,13 @@ struct rte_mbuf {
> void *buf_addr; /**< Virtual address of segment buffer. */
> phys_addr_t buf_physaddr; /**< Physical address of segment buffer. */
> uint16_t buf_len; /**< Length of segment buffer. */
> +
> + /* valid for any segment */
> + struct rte_mbuf *next; /**< Next segment of scattered packet. */
> + uint16_t data_off;
> + uint16_t data_len; /**< Amount of data in segment buffer. */
> + uint32_t pkt_len; /**< Total pkt len: sum of all segments. */
> +
Here, the compiler will add some padding between "buf_len" and "next"
(6 bytes in 64bits, 2 in 32bits). Shouldn't we add "reserved" fields
or at least a comment ? Another idea would be to reorganize the fields
to avoid padding, if possible.
Except this remarq, Acked-by: Olivier Matz <olivier.matz@6wind.com>
next prev parent reply other threads:[~2014-09-08 9:47 UTC|newest]
Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-03 15:49 [dpdk-dev] [PATCH 00/13] Mbuf Structure Rework, part 2 Bruce Richardson
2014-09-03 15:49 ` [dpdk-dev] [PATCH 01/13] mbuf: replace data pointer by an offset Bruce Richardson
2014-09-08 9:52 ` Olivier MATZ [this message]
2014-09-08 9:55 ` Olivier MATZ
2014-09-03 15:49 ` [dpdk-dev] [PATCH 02/13] mbuf: reorder fields by time of use Bruce Richardson
2014-09-08 10:17 ` Olivier MATZ
2014-09-03 15:49 ` [dpdk-dev] [PATCH 03/13] mbuf: add packet_type field Bruce Richardson
2014-09-08 10:17 ` Olivier MATZ
2014-09-08 10:33 ` Yerden Zhumabekov
2014-09-08 11:17 ` Olivier MATZ
2014-09-09 3:59 ` Zhang, Helin
[not found] ` <540EB428.9060706@6wind.com>
2014-09-09 8:45 ` Zhang, Helin
2014-09-09 9:47 ` Richardson, Bruce
2014-09-09 15:05 ` Jim Thompson
2014-09-03 15:49 ` [dpdk-dev] [PATCH 04/13] mbuf: expand ol_flags field to 64-bits Bruce Richardson
2014-09-08 10:25 ` Olivier MATZ
2014-09-09 9:00 ` Richardson, Bruce
2014-09-03 15:49 ` [dpdk-dev] [PATCH 05/13] mbuf: introduce a flag to indicate a control mbuf Bruce Richardson
2014-09-08 11:53 ` Olivier MATZ
2014-09-03 15:49 ` [dpdk-dev] [PATCH 06/13] mbuf: minor changes for readability Bruce Richardson
2014-09-08 12:03 ` Olivier MATZ
2014-09-03 15:49 ` [dpdk-dev] [PATCH 07/13] mbuf: use macros only to access the mbuf metadata Bruce Richardson
2014-09-08 12:05 ` Olivier MATZ
2014-09-09 9:01 ` Richardson, Bruce
2014-09-12 16:56 ` Dumitrescu, Cristian
2014-09-12 21:02 ` Olivier MATZ
2014-09-16 20:07 ` Dumitrescu, Cristian
2014-09-16 22:06 ` Ramia, Kannan Babu
2014-09-17 10:31 ` Richardson, Bruce
2014-09-17 14:01 ` Thomas Monjalon
2014-09-10 15:09 ` Bruce Richardson
2014-09-10 15:31 ` Olivier MATZ
2014-09-03 15:49 ` [dpdk-dev] [PATCH 08/13] mbuf: add named points inside the mbuf structure Bruce Richardson
2014-09-08 12:08 ` Olivier MATZ
2014-09-03 15:49 ` [dpdk-dev] [PATCH 09/13] ixgbe: rework vector pmd following mbuf changes Bruce Richardson
2014-09-03 15:49 ` [dpdk-dev] [PATCH 10/13] mbuf: split mbuf across two cache lines Bruce Richardson
2014-09-08 12:10 ` Olivier MATZ
2014-09-03 15:49 ` [dpdk-dev] [PATCH 11/13] mbuf: move l2_len and l3_len to second cache line Bruce Richardson
2014-09-04 5:08 ` Yerden Zhumabekov
2014-09-04 10:27 ` Bruce Richardson
2014-09-04 11:00 ` Yerden Zhumabekov
2014-09-04 11:55 ` Bruce Richardson
2014-09-03 15:49 ` [dpdk-dev] [PATCH 12/13] ixgbe: Fix perf regression due to moved pool ptr Bruce Richardson
2014-09-03 15:49 ` [dpdk-dev] [PATCH 13/13] ixgbe: Improve slow-path perf: vector scattered RX Bruce Richardson
2014-09-11 13:15 ` [dpdk-dev] [PATCH v2 00/13] Mbuf Structure Rework, part 2 Bruce Richardson
2014-09-11 13:15 ` [dpdk-dev] [PATCH v2 01/13] mbuf: replace data pointer by an offset Bruce Richardson
2014-09-11 13:15 ` [dpdk-dev] [PATCH v2 02/13] mbuf: reorder fields by time of use Bruce Richardson
2014-09-15 7:11 ` Liu, Jijiang
2014-09-15 8:19 ` Richardson, Bruce
2014-09-11 13:15 ` [dpdk-dev] [PATCH v2 03/13] mbuf: expand ol_flags field to 64-bits Bruce Richardson
2014-09-11 13:15 ` [dpdk-dev] [PATCH v2 04/13] mbuf: introduce a flag to indicate a control mbuf Bruce Richardson
2014-09-11 13:15 ` [dpdk-dev] [PATCH v2 05/13] mbuf: minor changes for readability Bruce Richardson
2014-09-11 13:15 ` [dpdk-dev] [PATCH v2 06/13] mbuf: use macros only to access the mbuf metadata Bruce Richardson
2014-09-11 13:15 ` [dpdk-dev] [PATCH v2 07/13] mbuf: move metadata macros to rte_port library Bruce Richardson
2014-09-11 13:15 ` [dpdk-dev] [PATCH v2 08/13] mbuf: add named points inside the mbuf structure Bruce Richardson
2014-09-11 13:15 ` [dpdk-dev] [PATCH v2 09/13] ixgbe: rework vector pmd following mbuf changes Bruce Richardson
2014-09-11 13:15 ` [dpdk-dev] [PATCH v2 10/13] mbuf: split mbuf across two cache lines Bruce Richardson
2014-09-11 13:15 ` [dpdk-dev] [PATCH v2 11/13] mbuf: move l2_len and l3_len to second cache line Bruce Richardson
2014-09-11 13:15 ` [dpdk-dev] [PATCH v2 12/13] ixgbe: Fix perf regression due to moved pool ptr Bruce Richardson
2014-09-15 16:20 ` [dpdk-dev] [PATCH v3 " Bruce Richardson
2014-09-11 13:15 ` [dpdk-dev] [PATCH v2 13/13] ixgbe: Improve slow-path perf: vector scattered RX Bruce Richardson
2014-09-17 22:35 ` [dpdk-dev] [PATCH v2 00/13] Mbuf Structure Rework, part 2 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=540D7C5F.8000406@6wind.com \
--to=olivier.matz@6wind.com \
--cc=bruce.richardson@intel.com \
--cc=dev@dpdk.org \
/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
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).