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From: Olivier Matz <olivier.matz@6wind.com>
To: Shijith Thotton <sthotton@marvell.com>
Cc: dev@dpdk.org, pbhagavatula@marvell.com,
	Honnappa.Nagarahalli@arm.com, bruce.richardson@intel.com,
	jerinj@marvell.com, mb@smartsharesystems.com,
	stephen@networkplumber.org, thomas@monjalon.net,
	david.marchand@redhat.com
Subject: Re: [PATCH v3 3/5] lib: move mbuf next pointer to first cache line
Date: Wed, 28 Sep 2022 14:52:54 +0200	[thread overview]
Message-ID: <YzRDpibcDrcUh7j8@platinum> (raw)
In-Reply-To: <7cc8107a4a83dbfe16abd1f24150b0db6cf1041b.1663767715.git.sthotton@marvell.com>

On Wed, Sep 21, 2022 at 07:26:19PM +0530, Shijith Thotton wrote:
> Swapped position of mbuf next pointer and second dynamic field (dynfield2)
> if the build is configured to use IOVA as VA. This is to move the mbuf
> next pointer to first cache line. kni library is disabled for this
> change as it depends on the offset value of next pointer.
> 
> Signed-off-by: Shijith Thotton <sthotton@marvell.com>
> ---
>  lib/mbuf/rte_mbuf_core.h | 29 +++++++++++++++++++++--------
>  lib/meson.build          |  3 +++
>  2 files changed, 24 insertions(+), 8 deletions(-)
> 
> diff --git a/lib/mbuf/rte_mbuf_core.h b/lib/mbuf/rte_mbuf_core.h
> index 94907f301d..915dcd8653 100644
> --- a/lib/mbuf/rte_mbuf_core.h
> +++ b/lib/mbuf/rte_mbuf_core.h
> @@ -590,11 +590,14 @@ struct rte_mbuf {
>  		 * working on vector drivers easier.
>  		 */
>  		rte_iova_t buf_iova __rte_aligned(sizeof(rte_iova_t));
> +#if RTE_IOVA_AS_VA
>  		/**
> -		 * Reserved for dynamic field in builds where physical address
> -		 * field is invalid.
> +		 * Next segment of scattered packet.
> +		 * This field is valid when physical address field is invalid.
> +		 * Otherwise next pointer in the second cache line will be used.
>  		 */
> -		uint64_t dynfield2;
> +		struct rte_mbuf *next;
> +#endif
>  	};
>  
>  	/* next 8 bytes are initialised on RX descriptor rearm */
> @@ -711,11 +714,21 @@ struct rte_mbuf {
>  	/* second cache line - fields only used in slow path or on TX */
>  	RTE_MARKER cacheline1 __rte_cache_min_aligned;
>  
> -	/**
> -	 * Next segment of scattered packet. Must be NULL in the last segment or
> -	 * in case of non-segmented packet.
> -	 */
> -	struct rte_mbuf *next;
> +	RTE_STD_C11
> +	union {
> +#if !RTE_IOVA_AS_VA
> +		/**
> +		 * Next segment of scattered packet. Must be NULL in the last
> +		 * segment or in case of non-segmented packet.
> +		 */
> +		struct rte_mbuf *next;
> +#endif
> +		/**
> +		 * Reserved for dynamic field when the next pointer is in first
> +		 * cache line (i.e. RTE_IOVA_AS_VA is 1).
> +		 */
> +		uint64_t dynfield2;
> +	};

Same comment than other patches about union vs #if.

>  
>  	/* fields to support TX offloads */
>  	RTE_STD_C11
> diff --git a/lib/meson.build b/lib/meson.build
> index c648f7d800..73d93bc803 100644
> --- a/lib/meson.build
> +++ b/lib/meson.build
> @@ -88,6 +88,9 @@ optional_libs = [
>  disabled_libs = []
>  opt_disabled_libs = run_command(list_dir_globs, get_option('disable_libs'),
>          check: true).stdout().split()
> +if dpdk_conf.get('RTE_IOVA_AS_VA') == 1
> +    opt_disabled_libs += ['kni']
> +endif

I guess this should be in the previous patch instead, since kni uses
m->buf_iova

>  foreach l:opt_disabled_libs
>      if not optional_libs.contains(l)
>          warning('Cannot disable mandatory library "@0@"'.format(l))


After this change, the documentation of RTE_IOVA_AS_VA can be enhanced to
explain that it also moves the next pointer to the first cache line, possibly
increasing the performance.

  parent reply	other threads:[~2022-09-28 12:52 UTC|newest]

Thread overview: 88+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-06-30 16:25 [PATCH] mbuf: add mbuf physical address field to dynamic field Shijith Thotton
2022-06-30 16:45 ` Stephen Hemminger
2022-07-01 12:16   ` Shijith Thotton
2022-07-01 12:24   ` Shijith Thotton
2022-07-03  7:31     ` Morten Brørup
2022-07-04 14:00       ` Bruce Richardson
2022-08-03 15:34         ` [EXT] " Shijith Thotton
2022-08-29 15:16           ` [PATCH v1 0/4] mbuf dynamic field expansion Shijith Thotton
2022-09-07 13:43             ` [PATCH v2 0/5] " Shijith Thotton
2022-09-21  9:43               ` David Marchand
2022-09-21 14:01                 ` [EXT] " Shijith Thotton
2022-09-21 13:56               ` [PATCH v3 " Shijith Thotton
2022-09-21 13:56                 ` [PATCH v3 1/5] build: add meson option to configure IOVA mode as VA Shijith Thotton
2022-09-28 12:52                   ` Olivier Matz
2022-09-29  5:48                     ` [EXT] " Shijith Thotton
2022-09-21 13:56                 ` [PATCH v3 2/5] mbuf: add second dynamic field member for VA only build Shijith Thotton
2022-09-28  7:24                   ` Thomas Monjalon
2022-09-28 12:52                     ` Olivier Matz
2022-09-28 19:33                       ` Thomas Monjalon
2022-09-28 19:48                       ` Stephen Hemminger
2022-09-29  6:13                         ` [EXT] " Shijith Thotton
2022-09-28 12:52                   ` Olivier Matz
2022-09-21 13:56                 ` [PATCH v3 3/5] lib: move mbuf next pointer to first cache line Shijith Thotton
2022-09-21 14:07                   ` Morten Brørup
2022-09-28 12:52                   ` Olivier Matz [this message]
2022-09-29  6:14                     ` [EXT] " Shijith Thotton
2022-09-21 13:56                 ` [PATCH v3 4/5] drivers: mark Marvell cnxk PMDs work with IOVA as VA Shijith Thotton
2022-09-28 12:53                   ` Olivier Matz
2022-09-29  6:19                     ` [EXT] " Shijith Thotton
2022-09-29  7:44                       ` Olivier Matz
2022-09-29  8:10                         ` Shijith Thotton
2022-10-07 20:17                   ` Olivier Matz
2022-10-07 20:22                     ` [EXT] " Shijith Thotton
2022-09-21 13:56                 ` [PATCH v3 5/5] drivers: mark software " Shijith Thotton
2022-09-28  5:41                 ` [PATCH v3 0/5] mbuf dynamic field expansion Shijith Thotton
2022-09-28 12:52                 ` Olivier Matz
2022-09-29  4:51                   ` [EXT] " Shijith Thotton
2022-10-07 13:50                 ` Thomas Monjalon
2022-10-07 19:35                   ` [EXT] " Shijith Thotton
2022-10-07 19:30                 ` [PATCH v4 0/7] " Shijith Thotton
2022-10-07 19:30                   ` [PATCH v4 1/7] mbuf: add API to get and set mbuf physical address Shijith Thotton
2022-10-07 20:16                     ` Olivier Matz
2022-10-07 20:20                       ` [EXT] " Shijith Thotton
2022-10-07 19:30                   ` [PATCH v4 2/7] test/dma: use API to get mbuf data " Shijith Thotton
2022-10-07 20:17                     ` Olivier Matz
2022-10-07 19:30                   ` [PATCH v4 3/7] build: add meson option to configure IOVA mode as PA Shijith Thotton
2022-10-07 19:30                   ` [PATCH v4 4/7] mbuf: add second dynamic field member Shijith Thotton
2022-10-07 19:30                   ` [PATCH v4 5/7] lib: move mbuf next pointer to first cache line Shijith Thotton
2022-10-07 19:30                   ` [PATCH v4 6/7] drivers: mark cnxk PMDs work with IOVA as PA disabled Shijith Thotton
2022-10-07 19:30                   ` [PATCH v4 7/7] drivers: mark software " Shijith Thotton
2022-10-07 20:19                   ` [PATCH v4 0/7] mbuf dynamic field expansion Olivier Matz
2022-10-07 21:02                   ` [PATCH v5 " Shijith Thotton
2022-10-07 21:02                     ` [PATCH v5 1/7] mbuf: add API to get and set mbuf physical address Shijith Thotton
2022-10-07 21:20                       ` Stephen Hemminger
2022-10-07 21:02                     ` [PATCH v5 2/7] test/dma: use API to get mbuf data " Shijith Thotton
2022-10-07 21:02                     ` [PATCH v5 3/7] build: add meson option to configure IOVA mode as PA Shijith Thotton
2022-10-07 21:02                     ` [PATCH v5 4/7] mbuf: add second dynamic field member Shijith Thotton
2022-10-07 21:02                     ` [PATCH v5 5/7] lib: move mbuf next pointer to first cache line Shijith Thotton
2022-10-07 21:22                       ` Stephen Hemminger
2022-10-07 21:30                         ` [EXT] " Shijith Thotton
2022-10-07 21:02                     ` [PATCH v5 6/7] drivers: mark cnxk PMDs work with IOVA as PA disabled Shijith Thotton
2022-10-07 21:02                     ` [PATCH v5 7/7] drivers: mark software " Shijith Thotton
2022-10-09  9:34                     ` [PATCH v5 0/7] mbuf dynamic field expansion Thomas Monjalon
2022-09-07 13:43             ` [PATCH v2 1/5] build: add meson option to configure IOVA mode as VA Shijith Thotton
2022-09-07 15:31               ` Stephen Hemminger
2022-09-07 15:38                 ` Bruce Richardson
2022-09-07 21:33                   ` Morten Brørup
2022-09-07 13:43             ` [PATCH v2 2/5] mbuf: add second dynamic field member for VA only build Shijith Thotton
2022-09-07 13:43             ` [PATCH v2 3/5] lib: move mbuf next pointer to first cache line Shijith Thotton
2022-09-07 13:43             ` [PATCH v2 4/5] drivers: mark Marvell cnxk PMDs work with IOVA as VA Shijith Thotton
2022-09-07 13:43             ` [PATCH v2 5/5] drivers: mark software " Shijith Thotton
2022-08-29 15:16           ` [PATCH v1 1/4] build: add meson option to configure IOVA mode " Shijith Thotton
2022-08-29 18:18             ` Morten Brørup
2022-08-30  8:32               ` Bruce Richardson
2022-08-29 15:16           ` [PATCH v1 2/4] mbuf: add second dynamic field member for VA only build Shijith Thotton
2022-08-29 18:32             ` Morten Brørup
2022-08-30  8:35               ` Bruce Richardson
2022-08-30  8:41                 ` [EXT] " Pavan Nikhilesh Bhagavatula
2022-08-30 13:22                   ` Honnappa Nagarahalli
2022-09-07 13:55                     ` Shijith Thotton
2022-08-29 15:16           ` [PATCH v1 3/4] drivers: mark Marvell cnxk PMDs work with IOVA as VA Shijith Thotton
2022-08-29 15:16           ` [PATCH v1 4/4] drivers: mark software " Shijith Thotton
2022-08-30 13:07     ` [PATCH] mbuf: add mbuf physical address field to dynamic field Ferruh Yigit
2022-09-12 13:19       ` [EXT] " Shijith Thotton
2022-06-30 16:55 ` Bruce Richardson
2022-07-01  9:48   ` Olivier Matz
2022-07-01 11:53     ` Slava Ovsiienko
2022-07-01 12:01     ` [EXT] " Shijith Thotton

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