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From: "Kinsella, Ray" <mdr@ashroe.eu>
To: Thomas Monjalon <thomas@monjalon.net>, dev@dpdk.org
Cc: ferruh.yigit@intel.com, david.marchand@redhat.com,
	bruce.richardson@intel.com, olivier.matz@6wind.com,
	andrew.rybchenko@oktetlabs.ru, jerinj@marvell.com,
	viacheslavo@nvidia.com, Neil Horman <nhorman@tuxdriver.com>
Subject: Re: [dpdk-dev] [PATCH 15/15] mbuf: move pool pointer in hotter first half
Date: Thu, 29 Oct 2020 14:42:46 +0000	[thread overview]
Message-ID: <29547082-92a3-2383-6476-1643f5eb07c2@ashroe.eu> (raw)
In-Reply-To: <20201029092751.3837177-16-thomas@monjalon.net>



On 29/10/2020 09:27, Thomas Monjalon wrote:
> The mempool pointer in the mbuf struct is moved
> from the second to the first half.
> It should increase performance on most systems having 64-byte cache line,
> i.e. mbuf is split in two cache lines.
> On such system, the first half (also called first cache line) is hotter
> than the second one where the pool pointer was.
> 
> Moving this field gives more space to dynfield1.
> 
> This is how the mbuf layout looks like (pahole-style):
> 
> word  type                              name                byte  size
>  0    void *                            buf_addr;         /*   0 +  8 */
>  1    rte_iova_t                        buf_iova          /*   8 +  8 */
>       /* --- RTE_MARKER64               rearm_data;                   */
>  2    uint16_t                          data_off;         /*  16 +  2 */
>       uint16_t                          refcnt;           /*  18 +  2 */
>       uint16_t                          nb_segs;          /*  20 +  2 */
>       uint16_t                          port;             /*  22 +  2 */
>  3    uint64_t                          ol_flags;         /*  24 +  8 */
>       /* --- RTE_MARKER                 rx_descriptor_fields1;        */
>  4    uint32_t             union        packet_type;      /*  32 +  4 */
>       uint32_t                          pkt_len;          /*  36 +  4 */
>  5    uint16_t                          data_len;         /*  40 +  2 */
>       uint16_t                          vlan_tci;         /*  42 +  2 */
>  5.5  uint64_t             union        hash;             /*  44 +  8 */
>  6.5  uint16_t                          vlan_tci_outer;   /*  52 +  2 */
>       uint16_t                          buf_len;          /*  54 +  2 */
>  7    struct rte_mempool *              pool;             /*  56 +  8 */
>       /* --- RTE_MARKER                 cacheline1;                   */
>  8    struct rte_mbuf *                 next;             /*  64 +  8 */
>  9    uint64_t             union        tx_offload;       /*  72 +  8 */
> 10    uint16_t                          priv_size;        /*  80 +  2 */
>       uint16_t                          timesync;         /*  82 +  2 */
>       uint32_t                          seqn;             /*  84 +  4 */
> 11    struct rte_mbuf_ext_shared_info * shinfo;           /*  88 +  8 */
> 12    uint64_t                          dynfield1[4];     /*  96 + 32 */
> 16    /* --- END                                             128      */
> 
> Signed-off-by: Thomas Monjalon <thomas@monjalon.net>
> ---
>  doc/guides/rel_notes/deprecation.rst | 5 -----
>  lib/librte_kni/rte_kni_common.h      | 3 ++-
>  lib/librte_mbuf/rte_mbuf_core.h      | 5 ++---
>  3 files changed, 4 insertions(+), 9 deletions(-)
> 
> diff --git a/doc/guides/rel_notes/deprecation.rst b/doc/guides/rel_notes/deprecation.rst
> index 72dbb25b83..07ca1dcbb2 100644
> --- a/doc/guides/rel_notes/deprecation.rst
> +++ b/doc/guides/rel_notes/deprecation.rst
> @@ -88,11 +88,6 @@ Deprecation Notices
>  
>    - ``seqn``
>  
> -  As a consequence, the layout of the ``struct rte_mbuf`` will be re-arranged,
> -  avoiding impact on vectorized implementation of the driver datapaths,
> -  while evaluating performance gains of a better use of the first cache line.
> -
> -
>  * ethdev: the legacy filter API, including
>    ``rte_eth_dev_filter_supported()``, ``rte_eth_dev_filter_ctrl()`` as well
>    as filter types MACVLAN, ETHERTYPE, FLEXIBLE, SYN, NTUPLE, TUNNEL, FDIR,
> diff --git a/lib/librte_kni/rte_kni_common.h b/lib/librte_kni/rte_kni_common.h
> index 36d66e2ffa..ffb3182731 100644
> --- a/lib/librte_kni/rte_kni_common.h
> +++ b/lib/librte_kni/rte_kni_common.h
> @@ -84,10 +84,11 @@ struct rte_kni_mbuf {
>  	char pad2[4];
>  	uint32_t pkt_len;       /**< Total pkt len: sum of all segment data_len. */
>  	uint16_t data_len;      /**< Amount of data in segment buffer. */
> +	char pad3[14];
> +	void *pool;
>  
>  	/* fields on second cache line */
>  	__attribute__((__aligned__(RTE_CACHE_LINE_MIN_SIZE)))
> -	void *pool;
>  	void *next;             /**< Physical address of next mbuf in kernel. */
>  };
>  
> diff --git a/lib/librte_mbuf/rte_mbuf_core.h b/lib/librte_mbuf/rte_mbuf_core.h
> index 52ca1c842f..ee185fa32b 100644
> --- a/lib/librte_mbuf/rte_mbuf_core.h
> +++ b/lib/librte_mbuf/rte_mbuf_core.h
> @@ -584,12 +584,11 @@ struct rte_mbuf {
>  
>  	uint16_t buf_len;         /**< Length of segment buffer. */
>  
> -	uint64_t unused;
> +	struct rte_mempool *pool; /**< Pool from which mbuf was allocated. */
>  
>  	/* second cache line - fields only used in slow path or on TX */
>  	RTE_MARKER cacheline1 __rte_cache_min_aligned;
>  
> -	struct rte_mempool *pool; /**< Pool from which mbuf was allocated. */
>  	struct rte_mbuf *next;    /**< Next segment of scattered packet. */
>  
>  	/* fields to support TX offloads */
> @@ -646,7 +645,7 @@ struct rte_mbuf {
>  	 */
>  	struct rte_mbuf_ext_shared_info *shinfo;
>  
> -	uint64_t dynfield1[3]; /**< Reserved for dynamic fields. */
> +	uint64_t dynfield1[4]; /**< Reserved for dynamic fields. */
>  } __rte_cache_aligned;
>  
>  /**
> 

I will let other chime in on the merits of positioning cache alignment of the 
mempool pointer. 

From the ABI PoV, depreciate notice has been observed and since mbuf effects 
everything doing it outside of a ABI Breakage window is impossible, so it now or
never.

Ray K



  parent reply	other threads:[~2020-10-29 14:43 UTC|newest]

Thread overview: 170+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-29  9:27 [dpdk-dev] [PATCH 00/15] remove mbuf timestamp Thomas Monjalon
2020-10-29  9:27 ` [dpdk-dev] [PATCH 01/15] eventdev: remove software Rx timestamp Thomas Monjalon
2020-10-29  9:27 ` [dpdk-dev] [PATCH 02/15] mbuf: add Rx timestamp dynamic flag Thomas Monjalon
2020-10-29  9:58   ` Andrew Rybchenko
2020-10-29 18:19     ` Ajit Khaparde
2020-10-29  9:27 ` [dpdk-dev] [PATCH 03/15] ethdev: register mbuf field and flags for timestamp Thomas Monjalon
2020-10-29 10:08   ` Andrew Rybchenko
2020-10-29 10:12     ` Thomas Monjalon
2020-10-29 10:33       ` Andrew Rybchenko
2020-10-29 10:46         ` Thomas Monjalon
2020-10-29  9:27 ` [dpdk-dev] [PATCH 04/15] latency: switch timestamp to dynamic mbuf field Thomas Monjalon
2020-10-29 10:13   ` Andrew Rybchenko
2020-10-29 10:40     ` Thomas Monjalon
2020-10-29 14:20   ` Pattan, Reshma
2020-10-29 16:15     ` Thomas Monjalon
2020-10-29  9:27 ` [dpdk-dev] [PATCH 05/15] net/ark: " Thomas Monjalon
2020-10-29  9:27 ` [dpdk-dev] [PATCH 06/15] net/dpaa2: " Thomas Monjalon
2020-10-29  9:27 ` [dpdk-dev] [PATCH 07/15] net/mlx5: fix dynamic mbuf offset lookup check Thomas Monjalon
2020-10-29  9:27 ` [dpdk-dev] [PATCH 08/15] net/mlx5: switch timestamp to dynamic mbuf field Thomas Monjalon
2020-10-29  9:27 ` [dpdk-dev] [PATCH 09/15] net/nfb: " Thomas Monjalon
2020-10-29  9:27 ` [dpdk-dev] [PATCH 10/15] net/octeontx2: " Thomas Monjalon
2020-10-29 11:02   ` Andrew Rybchenko
2020-10-29 11:34     ` Thomas Monjalon
2020-10-29 11:37       ` Andrew Rybchenko
2020-10-29 11:52     ` Slava Ovsiienko
2020-10-30 12:41       ` Jerin Jacob
2020-11-01 16:12         ` Thomas Monjalon
2020-11-01 20:00         ` Andrew Rybchenko
2020-10-29  9:27 ` [dpdk-dev] [PATCH 11/15] net/pcap: " Thomas Monjalon
2020-10-29  9:27 ` [dpdk-dev] [PATCH 12/15] app/testpmd: " Thomas Monjalon
2020-10-29 10:20   ` Andrew Rybchenko
2020-10-29 10:43     ` Thomas Monjalon
2020-10-29 10:52       ` Andrew Rybchenko
2020-10-29  9:27 ` [dpdk-dev] [PATCH 13/15] examples/rxtx_callbacks: switch timestamp to dynamic field Thomas Monjalon
2020-10-29 10:21   ` Andrew Rybchenko
2020-10-29 10:44     ` Thomas Monjalon
2020-10-29  9:27 ` [dpdk-dev] [PATCH 14/15] mbuf: remove deprecated timestamp field Thomas Monjalon
2020-10-29 10:23   ` Andrew Rybchenko
2020-10-29 18:18     ` Ajit Khaparde
2020-10-29 14:48   ` Kinsella, Ray
2020-10-29  9:27 ` [dpdk-dev] [PATCH 15/15] mbuf: move pool pointer in hotter first half Thomas Monjalon
2020-10-29 10:50   ` Andrew Rybchenko
2020-10-29 10:56     ` Thomas Monjalon
2020-10-29 14:15       ` Ananyev, Konstantin
2020-10-29 18:45         ` Ajit Khaparde
2020-10-31 18:20           ` [dpdk-dev] [PATCH 15/15] mbuf: move pool pointer in hotterfirst half Morten Brørup
2020-10-31 20:40             ` Thomas Monjalon
2020-11-01  9:12               ` Morten Brørup
2020-11-01 16:21                 ` Thomas Monjalon
2020-11-01 16:38                 ` Thomas Monjalon
2020-11-01 20:59                   ` Morten Brørup
2020-11-02 15:58                     ` Thomas Monjalon
2020-11-03 12:10                       ` Morten Brørup
2020-11-03 12:25                         ` Bruce Richardson
2020-11-03 13:46                           ` Morten Brørup
2020-11-03 13:50                             ` Bruce Richardson
2020-11-03 14:03                               ` Morten Brørup
2020-11-03 14:02                         ` Slava Ovsiienko
2020-11-03 15:03                           ` Morten Brørup
2020-11-04 15:00                             ` Olivier Matz
2020-11-05  0:25                               ` Ananyev, Konstantin
2020-11-05  9:04                                 ` Morten Brørup
2020-11-05  9:35                                 ` Morten Brørup
2020-11-05 10:29                                   ` Bruce Richardson
2020-10-29 14:42   ` Kinsella, Ray [this message]
2020-11-01 18:06 ` [dpdk-dev] [PATCH v2 00/14] remove mbuf timestamp Thomas Monjalon
2020-11-01 18:06   ` [dpdk-dev] [PATCH v2 01/14] eventdev: remove software Rx timestamp Thomas Monjalon
2020-11-01 18:06   ` [dpdk-dev] [PATCH v2 02/14] mbuf: add Rx timestamp dynamic flag Thomas Monjalon
2020-11-01 18:06   ` [dpdk-dev] [PATCH v2 03/14] ethdev: register mbuf field and flags for timestamp Thomas Monjalon
2020-11-02 15:39     ` Olivier Matz
2020-11-02 16:52       ` Thomas Monjalon
2020-11-01 18:06   ` [dpdk-dev] [PATCH v2 04/14] latency: switch timestamp to dynamic mbuf field Thomas Monjalon
2020-11-01 18:06   ` [dpdk-dev] [PATCH v2 05/14] net/ark: " Thomas Monjalon
2020-11-02 15:32     ` Olivier Matz
2020-11-02 16:10       ` Thomas Monjalon
2020-11-01 18:06   ` [dpdk-dev] [PATCH v2 06/14] net/dpaa2: " Thomas Monjalon
2020-11-01 18:06   ` [dpdk-dev] [PATCH v2 07/14] net/mlx5: fix dynamic mbuf offset lookup check Thomas Monjalon
2020-11-01 18:06   ` [dpdk-dev] [PATCH v2 08/14] net/mlx5: switch timestamp to dynamic mbuf field Thomas Monjalon
2020-11-02  5:08     ` Ruifeng Wang
2020-11-02 23:20     ` David Christensen
2020-11-01 18:06   ` [dpdk-dev] [PATCH v2 09/14] net/nfb: " Thomas Monjalon
2020-11-01 18:06   ` [dpdk-dev] [PATCH v2 10/14] net/octeontx2: " Thomas Monjalon
2020-11-01 18:28     ` Jerin Jacob
2020-11-02  9:38       ` Thomas Monjalon
2020-11-02 11:01         ` Thomas Monjalon
2020-11-01 18:06   ` [dpdk-dev] [PATCH v2 11/14] net/pcap: " Thomas Monjalon
2020-11-01 18:06   ` [dpdk-dev] [PATCH v2 12/14] app/testpmd: " Thomas Monjalon
2020-11-01 18:06   ` [dpdk-dev] [PATCH v2 13/14] examples/rxtx_callbacks: switch timestamp to dynamic field Thomas Monjalon
2020-11-01 18:06   ` [dpdk-dev] [PATCH v2 14/14] mbuf: remove deprecated timestamp field Thomas Monjalon
2020-11-02 15:41     ` Olivier Matz
2020-11-02 15:47       ` David Marchand
2020-11-02 15:49         ` Thomas Monjalon
2020-11-01 18:08   ` [dpdk-dev] [PATCH v2 00/14] remove mbuf timestamp Thomas Monjalon
2020-11-03  0:13 ` [dpdk-dev] [PATCH v3 00/16] " Thomas Monjalon
2020-11-03  0:13   ` [dpdk-dev] [PATCH v3 01/16] eventdev: remove software Rx timestamp Thomas Monjalon
2020-11-03  0:13   ` [dpdk-dev] [PATCH v3 02/16] mbuf: add Rx timestamp flag and helpers Thomas Monjalon
2020-11-03  9:33     ` Olivier Matz
2020-11-03  9:59       ` Thomas Monjalon
2020-11-03  0:13   ` [dpdk-dev] [PATCH v3 03/16] latency: switch Rx timestamp to dynamic mbuf field Thomas Monjalon
2020-11-03  0:13   ` [dpdk-dev] [PATCH v3 04/16] net/ark: " Thomas Monjalon
2020-11-03  0:13   ` [dpdk-dev] [PATCH v3 05/16] net/dpaa2: " Thomas Monjalon
2020-11-03  9:18     ` Hemant Agrawal
2020-11-03  0:13   ` [dpdk-dev] [PATCH v3 06/16] net/mlx5: fix dynamic mbuf offset lookup check Thomas Monjalon
2020-11-03  8:12     ` Slava Ovsiienko
2020-11-03  0:13   ` [dpdk-dev] [PATCH v3 07/16] net/mlx5: switch Rx timestamp to dynamic mbuf field Thomas Monjalon
2020-11-03  8:12     ` Slava Ovsiienko
2020-11-03  0:13   ` [dpdk-dev] [PATCH v3 08/16] net/nfb: " Thomas Monjalon
2020-11-03 10:20     ` Olivier Matz
2020-11-03  0:14   ` [dpdk-dev] [PATCH v3 09/16] net/octeontx2: " Thomas Monjalon
2020-11-03 10:52     ` Harman Kalra
2020-11-03 11:22       ` Thomas Monjalon
2020-11-03 12:21         ` Thomas Monjalon
2020-11-03 14:23           ` [dpdk-dev] [EXT] " Harman Kalra
2020-11-03  0:14   ` [dpdk-dev] [PATCH v3 10/16] net/pcap: " Thomas Monjalon
2020-11-03  0:14   ` [dpdk-dev] [PATCH v3 11/16] app/testpmd: " Thomas Monjalon
2020-11-03 10:23     ` Olivier Matz
2020-11-03  0:14   ` [dpdk-dev] [PATCH v3 12/16] examples/rxtx_callbacks: switch timestamp to dynamic field Thomas Monjalon
2020-11-03  0:14   ` [dpdk-dev] [PATCH v3 13/16] ethdev: add doxygen comment for Rx timestamp API Thomas Monjalon
2020-11-03  0:14   ` [dpdk-dev] [PATCH v3 14/16] mbuf: remove deprecated timestamp field Thomas Monjalon
2020-11-03  0:14   ` [dpdk-dev] [PATCH v3 15/16] mbuf: add Tx timestamp registration helper Thomas Monjalon
2020-11-03  0:14   ` [dpdk-dev] [PATCH v3 16/16] ethdev: include mbuf registration in Tx timestamp API Thomas Monjalon
2020-11-03  7:54     ` Slava Ovsiienko
2020-11-03  9:00   ` [dpdk-dev] [PATCH v3 00/16] remove mbuf timestamp David Marchand
2020-11-03 12:21 ` [dpdk-dev] [PATCH v4 " Thomas Monjalon
2020-11-03 12:21   ` [dpdk-dev] [PATCH v4 01/16] eventdev: remove software Rx timestamp Thomas Monjalon
2020-11-03 12:21   ` [dpdk-dev] [PATCH v4 02/16] mbuf: add Rx timestamp flag and helpers Thomas Monjalon
2020-11-03 12:34     ` Andrew Rybchenko
2020-11-03 12:21   ` [dpdk-dev] [PATCH v4 03/16] latency: switch Rx timestamp to dynamic mbuf field Thomas Monjalon
2020-11-03 12:21   ` [dpdk-dev] [PATCH v4 04/16] net/ark: " Thomas Monjalon
2020-11-03 12:37     ` Andrew Rybchenko
2020-11-03 13:08       ` Thomas Monjalon
2020-11-03 12:21   ` [dpdk-dev] [PATCH v4 05/16] net/dpaa2: " Thomas Monjalon
2020-11-03 12:21   ` [dpdk-dev] [PATCH v4 06/16] net/mlx5: fix dynamic mbuf offset lookup check Thomas Monjalon
2020-11-03 12:21   ` [dpdk-dev] [PATCH v4 07/16] net/mlx5: switch Rx timestamp to dynamic mbuf field Thomas Monjalon
2020-11-03 12:21   ` [dpdk-dev] [PATCH v4 08/16] net/nfb: " Thomas Monjalon
2020-11-03 12:21   ` [dpdk-dev] [PATCH v4 09/16] net/octeontx2: " Thomas Monjalon
2020-11-03 12:21   ` [dpdk-dev] [PATCH v4 10/16] net/pcap: " Thomas Monjalon
2020-11-03 12:22   ` [dpdk-dev] [PATCH v4 11/16] app/testpmd: " Thomas Monjalon
2020-11-03 12:22   ` [dpdk-dev] [PATCH v4 12/16] examples/rxtx_callbacks: switch timestamp to dynamic field Thomas Monjalon
2020-11-03 12:22   ` [dpdk-dev] [PATCH v4 13/16] ethdev: add doxygen comment for Rx timestamp API Thomas Monjalon
2020-11-03 12:40     ` Andrew Rybchenko
2020-11-03 12:22   ` [dpdk-dev] [PATCH v4 14/16] mbuf: remove deprecated timestamp field Thomas Monjalon
2020-11-03 12:22   ` [dpdk-dev] [PATCH v4 15/16] mbuf: add Tx timestamp registration helper Thomas Monjalon
2020-11-03 12:42     ` Andrew Rybchenko
2020-11-03 12:22   ` [dpdk-dev] [PATCH v4 16/16] ethdev: include mbuf registration in Tx timestamp API Thomas Monjalon
2020-11-03 12:45     ` Andrew Rybchenko
2020-11-03 14:09 ` [dpdk-dev] [PATCH v5 00/16] remove mbuf timestamp Thomas Monjalon
2020-11-03 14:09   ` [dpdk-dev] [PATCH v5 01/16] eventdev: remove software Rx timestamp Thomas Monjalon
2020-11-03 14:09   ` [dpdk-dev] [PATCH v5 02/16] mbuf: add Rx timestamp flag and helpers Thomas Monjalon
2020-11-03 14:09   ` [dpdk-dev] [PATCH v5 03/16] latency: switch Rx timestamp to dynamic mbuf field Thomas Monjalon
2020-11-03 14:09   ` [dpdk-dev] [PATCH v5 04/16] net/ark: " Thomas Monjalon
2020-11-03 14:09   ` [dpdk-dev] [PATCH v5 05/16] net/dpaa2: " Thomas Monjalon
2020-11-03 14:09   ` [dpdk-dev] [PATCH v5 06/16] net/mlx5: fix dynamic mbuf offset lookup check Thomas Monjalon
2020-11-03 14:09   ` [dpdk-dev] [PATCH v5 07/16] net/mlx5: switch Rx timestamp to dynamic mbuf field Thomas Monjalon
2020-11-03 14:09   ` [dpdk-dev] [PATCH v5 08/16] net/nfb: " Thomas Monjalon
2020-11-03 14:09   ` [dpdk-dev] [PATCH v5 09/16] net/octeontx2: " Thomas Monjalon
2020-11-03 14:09   ` [dpdk-dev] [PATCH v5 10/16] net/pcap: " Thomas Monjalon
2020-11-03 14:09   ` [dpdk-dev] [PATCH v5 11/16] app/testpmd: " Thomas Monjalon
2020-11-03 14:09   ` [dpdk-dev] [PATCH v5 12/16] examples/rxtx_callbacks: switch timestamp to dynamic field Thomas Monjalon
2020-11-03 14:09   ` [dpdk-dev] [PATCH v5 13/16] ethdev: add doxygen comment for Rx timestamp API Thomas Monjalon
2020-11-03 19:07     ` Ajit Khaparde
2020-11-03 14:09   ` [dpdk-dev] [PATCH v5 14/16] mbuf: remove deprecated timestamp field Thomas Monjalon
2020-11-03 14:09   ` [dpdk-dev] [PATCH v5 15/16] mbuf: add Tx timestamp registration helper Thomas Monjalon
2020-11-03 14:09   ` [dpdk-dev] [PATCH v5 16/16] ethdev: include mbuf registration in Tx timestamp API Thomas Monjalon
2020-11-03 14:17   ` [dpdk-dev] [PATCH v5 00/16] remove mbuf timestamp Olivier Matz
2020-11-03 14:44     ` Thomas Monjalon
2020-11-03 16:08   ` Stephen Hemminger
2020-11-03 16:20     ` Thomas Monjalon
2020-11-03 17:42       ` Stephen Hemminger
2020-11-03 17:55         ` Thomas Monjalon

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