Re: [dpdk-dev] [PATCH v8 3/3] ixgbe: Add LRO support

[Vlad Zolotarov <vladz@cloudius-systems.com>]

On 03/30/15 18:37, Vlad Zolotarov wrote:
>
>
> On 03/30/15 17:18, Ananyev, Konstantin wrote:
>> Hi Vlad,
>>
>>> -----Original Message-----
>>> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Vlad Zolotarov
>>> Sent: Wednesday, March 18, 2015 5:52 PM
>>> To: dev@dpdk.org
>>> Subject: [dpdk-dev] [PATCH v8 3/3] ixgbe: Add LRO support
>>>
>>>      - Only x540 and 82599 devices support LRO.
>>>      - Add the appropriate HW configuration.
>>>      - Add RSC aware rx_pkt_burst() handlers:
>>>         - Implemented bulk allocation and non-bulk allocation versions.
>>>         - Add LRO-specific fields to rte_eth_rxmode, to 
>>> rte_eth_dev_data
>>>           and to ixgbe_rx_queue.
>>>         - Use the appropriate handler when LRO is requested.
>>>
>>> Signed-off-by: Vlad Zolotarov <vladz@cloudius-systems.com>
>>> ---
>>> New in v8:
>>>     - Took the RSC configuration code from ixgbe_dev_rx_init() into 
>>> a separate
>>>       function - ixgbe_set_rsc().
>>>     - Added some missing macros for HW configuration.
>>>     - Styling adjustments:
>>>        - Functions names.
>>>        - Functions descriptions.
>>>     - Reworked the ixgbe_free_rsc_cluster() code to make it more 
>>> readable.
>>>     - Kill the HEADER_SPLIT flow in ixgbe_set_rsc() since it's not 
>>> supported by
>>>       ixgbe PMD.
>>>
>>> New in v7:
>>>     - Free not-yet-completed RSC aggregations in rte_eth_dev_stop() 
>>> flow.
>>>     - Reset the sw_ring[].mbuf entry in a bulk allocation case.
>>>       This is needed for ixgbe_rx_queue_release_mbufs().
>>>     - _recv_pkts_lro(): added the missing memory barrier before RDT 
>>> update in a
>>>       non-bulk allocation case.
>>>     - Don't allow RSC when device is configured in an SR-IOV mode.
>>>
>>> New in v5:
>>>     - Put the RTE_ETHDEV_HAS_LRO_SUPPORT definition at the beginning 
>>> of rte_ethdev.h.
>>>     - Removed the "TODO: Remove me" comment near 
>>> RTE_ETHDEV_HAS_LRO_SUPPORT.
>>>
>>> New in v4:
>>>     - Define RTE_ETHDEV_HAS_LRO_SUPPORT in rte_ethdev.h instead of
>>>       RTE_ETHDEV_LRO_SUPPORT defined in config/common_linuxapp.
>>>
>>> New in v2:
>>>     - Removed rte_eth_dev_data.lro_bulk_alloc.
>>>     - Fixed a few styling and spelling issues.
>>> ---
>>>   lib/librte_ether/rte_ethdev.h           |   9 +-
>>>   lib/librte_net/rte_ip.h                 |   3 +
>>>   lib/librte_pmd_ixgbe/ixgbe/ixgbe_type.h |   6 +
>>>   lib/librte_pmd_ixgbe/ixgbe_ethdev.c     |  11 +
>>>   lib/librte_pmd_ixgbe/ixgbe_ethdev.h     |   5 +
>>>   lib/librte_pmd_ixgbe/ixgbe_rxtx.c       | 610 
>>> +++++++++++++++++++++++++++++++-
>>>   lib/librte_pmd_ixgbe/ixgbe_rxtx.h       |   6 +
>>>   7 files changed, 642 insertions(+), 8 deletions(-)
>>>
>>> diff --git a/lib/librte_ether/rte_ethdev.h 
>>> b/lib/librte_ether/rte_ethdev.h
>>> index 21aa359..61dc49a 100644
>>> --- a/lib/librte_ether/rte_ethdev.h
>>> +++ b/lib/librte_ether/rte_ethdev.h
>>> @@ -172,6 +172,9 @@ extern "C" {
>>>
>>>   #include <stdint.h>
>>>
>>> +/* Use this macro to check if LRO API is supported */
>>> +#define RTE_ETHDEV_HAS_LRO_SUPPORT
>>> +
>>>   #include <rte_log.h>
>>>   #include <rte_interrupts.h>
>>>   #include <rte_pci.h>
>>> @@ -320,14 +323,15 @@ struct rte_eth_rxmode {
>>>       enum rte_eth_rx_mq_mode mq_mode;
>>>       uint32_t max_rx_pkt_len;  /**< Only used if jumbo_frame 
>>> enabled. */
>>>       uint16_t split_hdr_size;  /**< hdr buf size (header_split 
>>> enabled).*/
>>> -    uint8_t header_split : 1, /**< Header Split enable. */
>>> +    uint16_t header_split : 1, /**< Header Split enable. */
>>>           hw_ip_checksum   : 1, /**< IP/UDP/TCP checksum offload 
>>> enable. */
>>>           hw_vlan_filter   : 1, /**< VLAN filter enable. */
>>>           hw_vlan_strip    : 1, /**< VLAN strip enable. */
>>>           hw_vlan_extend   : 1, /**< Extended VLAN enable. */
>>>           jumbo_frame      : 1, /**< Jumbo Frame Receipt enable. */
>>>           hw_strip_crc     : 1, /**< Enable CRC stripping by 
>>> hardware. */
>>> -        enable_scatter   : 1; /**< Enable scatter packets rx 
>>> handler */
>>> +        enable_scatter   : 1, /**< Enable scatter packets rx 
>>> handler */
>>> +        enable_lro       : 1; /**< Enable LRO */
>>>   };
>>>
>>>   /**
>>> @@ -1515,6 +1519,7 @@ struct rte_eth_dev_data {
>>>       uint8_t port_id;           /**< Device [external] port 
>>> identifier. */
>>>       uint8_t promiscuous   : 1, /**< RX promiscuous mode ON(1) / 
>>> OFF(0). */
>>>           scattered_rx : 1,  /**< RX of scattered packets is ON(1) / 
>>> OFF(0) */
>>> +        lro          : 1,  /**< RX LRO is ON(1) / OFF(0) */
>>>           all_multicast : 1, /**< RX all multicast mode ON(1) / 
>>> OFF(0). */
>>>           dev_started : 1;   /**< Device state: STARTED(1) / 
>>> STOPPED(0). */
>>>   };
>>> diff --git a/lib/librte_net/rte_ip.h b/lib/librte_net/rte_ip.h
>>> index 64935d9..74c9ced 100644
>>> --- a/lib/librte_net/rte_ip.h
>>> +++ b/lib/librte_net/rte_ip.h
>>> @@ -110,6 +110,9 @@ struct ipv4_hdr {
>>>                          (((c) & 0xff) << 8)  | \
>>>                          ((d) & 0xff))
>>>
>>> +/** Maximal IPv4 packet length (including a header) */
>>> +#define IPV4_MAX_PKT_LEN        65535
>>> +
>>>   /** Internet header length mask for version_ihl field */
>>>   #define IPV4_HDR_IHL_MASK    (0x0f)
>>>   /**
>>> diff --git a/lib/librte_pmd_ixgbe/ixgbe/ixgbe_type.h 
>>> b/lib/librte_pmd_ixgbe/ixgbe/ixgbe_type.h
>>> index 9a66370..4998627 100644
>>> --- a/lib/librte_pmd_ixgbe/ixgbe/ixgbe_type.h
>>> +++ b/lib/librte_pmd_ixgbe/ixgbe/ixgbe_type.h
>>> @@ -234,8 +234,14 @@ struct ixgbe_thermal_sensor_data {
>>>   #define IXGBE_EITR(_i)        (((_i) <= 23) ? (0x00820 + ((_i) * 
>>> 4)) : \
>>>                    (0x012300 + (((_i) - 24) * 4)))
>>>   #define IXGBE_EITR_ITR_INT_MASK    0x00000FF8
>>> +#define IXGBE_EITR_ITR_INT_SHIFT 3
>>>   #define IXGBE_EITR_LLI_MOD    0x00008000
>>>   #define IXGBE_EITR_CNT_WDIS    0x80000000
>>> +/* EITR Inteval is in 2048ns uinits for 1G and 10G link */
>>> +#define IXGBE_EITR_INTERVAL_UNIT_NS    2048
>> Why is that? Why not just 2us as 82599 spec says?
>> And then:
>> +#define IXGBE_EITR_INTERVAL_US(us) (((us) / 
>> IXGBE_EITR_INTERVAL_UNIT_US << IXGBE_EITR_ITR_INT_SHIFT) & 
>> IXGBE_EITR_ITR_INT_MASK)
>> ?
>
> Because spec doesn't say 2us but rather 2.048us - see 8.2.4.5.16 
> chapter of x540 spec.

The most confusing part is that 82599 Rev. 3.0 spec does say so. The 
x540 spec I have is dated by March 2014 and 82599 spec is dated by 
November 2014 but according to changelog EITR description has never been 
updated. Therefore I conclude that the more recent device spec (x540) 
holds the most up to date content.

Pls., confirm.

thanks,
vlad

>
>>
>>> +#define IXGBE_EITR_INTERVAL_US(us)    \
>>> +   (((us) * 1000 / IXGBE_EITR_INTERVAL_UNIT_NS << 
>>> IXGBE_EITR_ITR_INT_SHIFT) & \
>>> +        IXGBE_EITR_ITR_INT_MASK)
>>
>> Unfortunately we are not supposed to change files under ixgbe 
>> subfirectory (except ixgbe_osdep.*).
>> These files comes from ixgbe shared code and we treat them as read-only.
>> You need to move these new macros you added into ixgbe_ethedev.h.
>
> Aha... Ok. No problem.
>
>>
>> All other things look good to me.
>> Konstantin
>>
>>>   #define IXGBE_IVAR(_i)        (0x00900 + ((_i) * 4)) /* 24 at 
>>> 0x900-0x960 */
>>>   #define IXGBE_IVAR_MISC        0x00A00 /* misc MSI-X interrupt 
>>> causes */
>>>   #define IXGBE_EITRSEL        0x00894
>>> diff --git a/lib/librte_pmd_ixgbe/ixgbe_ethdev.c 
>>> b/lib/librte_pmd_ixgbe/ixgbe_ethdev.c
>>> index 92d75db..923692e 100644
>>> --- a/lib/librte_pmd_ixgbe/ixgbe_ethdev.c
>>> +++ b/lib/librte_pmd_ixgbe/ixgbe_ethdev.c
>>> @@ -1645,6 +1645,7 @@ ixgbe_dev_stop(struct rte_eth_dev *dev)
>>>
>>>       /* Clear stored conf */
>>>       dev->data->scattered_rx = 0;
>>> +    dev->data->lro = 0;
>>>
>>>       /* Clear recorded link status */
>>>       memset(&link, 0, sizeof(link));
>>> @@ -2013,6 +2014,16 @@ ixgbe_dev_info_get(struct rte_eth_dev *dev, 
>>> struct rte_eth_dev_info *dev_info)
>>>           DEV_RX_OFFLOAD_IPV4_CKSUM |
>>>           DEV_RX_OFFLOAD_UDP_CKSUM  |
>>>           DEV_RX_OFFLOAD_TCP_CKSUM;
>>> +
>>> +    /*
>>> +     * RSC is only supported by 82599 and x540 PF devices in a 
>>> non-SR-IOV
>>> +     * mode.
>>> +     */
>>> +    if ((hw->mac.type == ixgbe_mac_82599EB ||
>>> +         hw->mac.type == ixgbe_mac_X540) &&
>>> +        !RTE_ETH_DEV_SRIOV(dev).active)
>>> +        dev_info->rx_offload_capa |= DEV_RX_OFFLOAD_TCP_LRO;
>>> +
>>>       dev_info->tx_offload_capa =
>>>           DEV_TX_OFFLOAD_VLAN_INSERT |
>>>           DEV_TX_OFFLOAD_IPV4_CKSUM  |
>>> diff --git a/lib/librte_pmd_ixgbe/ixgbe_ethdev.h 
>>> b/lib/librte_pmd_ixgbe/ixgbe_ethdev.h
>>> index ffe3471..7050340 100644
>>> --- a/lib/librte_pmd_ixgbe/ixgbe_ethdev.h
>>> +++ b/lib/librte_pmd_ixgbe/ixgbe_ethdev.h
>>> @@ -344,6 +344,11 @@ uint16_t ixgbe_recv_pkts(void *rx_queue, struct 
>>> rte_mbuf **rx_pkts,
>>>   uint16_t ixgbe_recv_scattered_pkts(void *rx_queue,
>>>           struct rte_mbuf **rx_pkts, uint16_t nb_pkts);
>>>
>>> +uint16_t ixgbe_recv_pkts_lro_single_alloc(void *rx_queue,
>>> +        struct rte_mbuf **rx_pkts, uint16_t nb_pkts);
>>> +uint16_t ixgbe_recv_pkts_lro_bulk_alloc(void *rx_queue,
>>> +        struct rte_mbuf **rx_pkts, uint16_t nb_pkts);
>>> +
>>>   uint16_t ixgbe_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts,
>>>           uint16_t nb_pkts);
>>>
>>> diff --git a/lib/librte_pmd_ixgbe/ixgbe_rxtx.c 
>>> b/lib/librte_pmd_ixgbe/ixgbe_rxtx.c
>>> index a08ae6a..daa4c45 100644
>>> --- a/lib/librte_pmd_ixgbe/ixgbe_rxtx.c
>>> +++ b/lib/librte_pmd_ixgbe/ixgbe_rxtx.c
>>> @@ -70,6 +70,7 @@
>>>   #include <rte_sctp.h>
>>>   #include <rte_string_fns.h>
>>>   #include <rte_errno.h>
>>> +#include <rte_ip.h>
>>>
>>>   #include "ixgbe_logs.h"
>>>   #include "ixgbe/ixgbe_api.h"
>>> @@ -1422,6 +1423,295 @@ ixgbe_fill_cluster_head_buf(
>>>       }
>>>   }
>>>
>>> +/**
>>> + * ixgbe_recv_pkts_lro - receive handler for and LRO case.
>>> + *
>>> + * @rx_queue Rx queue handle
>>> + * @rx_pkts table of received packets
>>> + * @nb_pkts size of rx_pkts table
>>> + * @bulk_alloc if TRUE bulk allocation is used for a HW ring refilling
>>> + *
>>> + * Handles the Rx HW ring completions when RSC feature is 
>>> configured. Uses an
>>> + * additional ring of ixgbe_rsc_entry's that will hold the relevant 
>>> RSC info.
>>> + *
>>> + * We use the same logic as in Lunux and in FreeBSD ixgbe drivers:
>>> + * 1) When non-EOP RSC completion arrives:
>>> + *    a) Update the HEAD of the current RSC aggregation cluster 
>>> with the new
>>> + *       segment's data length.
>>> + *    b) Set the "next" pointer of the current segment to point to 
>>> the segment
>>> + *       at the NEXTP index.
>>> + *    c) Pass the HEAD of RSC aggregation cluster on to the next 
>>> NEXTP entry
>>> + *       in the sw_rsc_ring.
>>> + * 2) When EOP arrives we just update the cluster's total length 
>>> and offload
>>> + *    flags and deliver the cluster up to the upper layers. In our 
>>> case - put it
>>> + *    in the rx_pkts table.
>>> + *
>>> + * Returns the number of received packets/clusters (according to 
>>> the "bulk
>>> + * receive" interface).
>>> + */
>>> +static inline uint16_t
>>> +ixgbe_recv_pkts_lro(void *rx_queue, struct rte_mbuf **rx_pkts, 
>>> uint16_t nb_pkts,
>>> +            bool bulk_alloc)
>>> +{
>>> +    struct ixgbe_rx_queue *rxq = rx_queue;
>>> +    volatile union ixgbe_adv_rx_desc *rx_ring = rxq->rx_ring;
>>> +    struct ixgbe_rx_entry *sw_ring = rxq->sw_ring;
>>> +    struct ixgbe_rsc_entry *sw_rsc_ring = rxq->sw_rsc_ring;
>>> +    uint16_t rx_id = rxq->rx_tail;
>>> +    uint16_t nb_rx = 0;
>>> +    uint16_t nb_hold = rxq->nb_rx_hold;
>>> +    uint16_t prev_id = rxq->rx_tail;
>>> +
>>> +    while (nb_rx < nb_pkts) {
>>> +        bool eop;
>>> +        struct ixgbe_rx_entry *rxe;
>>> +        struct ixgbe_rsc_entry *rsc_entry;
>>> +        struct ixgbe_rsc_entry *next_rsc_entry;
>>> +        struct ixgbe_rx_entry *next_rxe;
>>> +        struct rte_mbuf *first_seg;
>>> +        struct rte_mbuf *rxm;
>>> +        struct rte_mbuf *nmb;
>>> +        union ixgbe_adv_rx_desc rxd;
>>> +        uint16_t data_len;
>>> +        uint16_t next_id;
>>> +        volatile union ixgbe_adv_rx_desc *rxdp;
>>> +        uint32_t staterr;
>>> +
>>> +next_desc:
>>> +        /*
>>> +         * The code in this whole file uses the volatile pointer to
>>> +         * ensure the read ordering of the status and the rest of the
>>> +         * descriptor fields (on the compiler level only!!!). This 
>>> is so
>>> +         * UGLY - why not to just use the compiler barrier instead? 
>>> DPDK
>>> +         * even has the rte_compiler_barrier() for that.
>>> +         *
>>> +         * But most importantly this is just wrong because this 
>>> doesn't
>>> +         * ensure memory ordering in a general case at all. For
>>> +         * instance, DPDK is supposed to work on Power CPUs where
>>> +         * compiler barrier may just not be enough!
>>> +         *
>>> +         * I tried to write only this function properly to have a
>>> +         * starting point (as a part of an LRO/RSC series) but the
>>> +         * compiler cursed at me when I tried to cast away the
>>> +         * "volatile" from rx_ring (yes, it's volatile too!!!). So, 
>>> I'm
>>> +         * keeping it the way it is for now.
>>> +         *
>>> +         * The code in this file is broken in so many other places and
>>> +         * will just not work on a big endian CPU anyway therefore the
>>> +         * lines below will have to be revisited together with the 
>>> rest
>>> +         * of the ixgbe PMD.
>>> +         *
>>> +         * TODO:
>>> +         *    - Get rid of "volatile" crap and let the compiler do its
>>> +         *      job.
>>> +         *    - Use the proper memory barrier (rte_rmb()) to ensure 
>>> the
>>> +         *      memory ordering below.
>>> +         */
>>> +        rxdp = &rx_ring[rx_id];
>>> +        staterr = rte_le_to_cpu_32(rxdp->wb.upper.status_error);
>>> +
>>> +        if (!(staterr & IXGBE_RXDADV_STAT_DD))
>>> +            break;
>>> +
>>> +        rxd = *rxdp;
>>> +
>>> +        PMD_RX_LOG(DEBUG, "port_id=%u queue_id=%u rx_id=%u "
>>> +                  "staterr=0x%x data_len=%u",
>>> +               rxq->port_id, rxq->queue_id, rx_id, staterr,
>>> +               rte_le_to_cpu_16(rxd.wb.upper.length));
>>> +
>>> +        if (!bulk_alloc) {
>>> +            nmb = rte_rxmbuf_alloc(rxq->mb_pool);
>>> +            if (nmb == NULL) {
>>> +                PMD_RX_LOG(DEBUG, "RX mbuf alloc failed "
>>> +                          "port_id=%u queue_id=%u",
>>> +                       rxq->port_id, rxq->queue_id);
>>> +
>>> +                rte_eth_devices[rxq->port_id].data->
>>> +                            rx_mbuf_alloc_failed++;
>>> +                break;
>>> +            }
>>> +        } else if (nb_hold > rxq->rx_free_thresh) {
>>> +            uint16_t next_rdt = rxq->rx_free_trigger;
>>> +
>>> +            if (!ixgbe_rx_alloc_bufs(rxq, false)) {
>>> +                rte_wmb();
>>> +                IXGBE_PCI_REG_WRITE(rxq->rdt_reg_addr,
>>> +                            next_rdt);
>>> +                nb_hold -= rxq->rx_free_thresh;
>>> +            } else {
>>> +                PMD_RX_LOG(DEBUG, "RX bulk alloc failed "
>>> +                          "port_id=%u queue_id=%u",
>>> +                       rxq->port_id, rxq->queue_id);
>>> +
>>> +                rte_eth_devices[rxq->port_id].data->
>>> +                            rx_mbuf_alloc_failed++;
>>> +                break;
>>> +            }
>>> +        }
>>> +
>>> +        nb_hold++;
>>> +        rxe = &sw_ring[rx_id];
>>> +        eop = staterr & IXGBE_RXDADV_STAT_EOP;
>>> +
>>> +        next_id = rx_id + 1;
>>> +        if (next_id == rxq->nb_rx_desc)
>>> +            next_id = 0;
>>> +
>>> +        /* Prefetch next mbuf while processing current one. */
>>> +        rte_ixgbe_prefetch(sw_ring[next_id].mbuf);
>>> +
>>> +        /*
>>> +         * When next RX descriptor is on a cache-line boundary,
>>> +         * prefetch the next 4 RX descriptors and the next 4 pointers
>>> +         * to mbufs.
>>> +         */
>>> +        if ((next_id & 0x3) == 0) {
>>> +            rte_ixgbe_prefetch(&rx_ring[next_id]);
>>> +            rte_ixgbe_prefetch(&sw_ring[next_id]);
>>> +        }
>>> +
>>> +        rxm = rxe->mbuf;
>>> +
>>> +        if (!bulk_alloc) {
>>> +            __le64 dma =
>>> + rte_cpu_to_le_64(RTE_MBUF_DATA_DMA_ADDR_DEFAULT(nmb));
>>> +            /*
>>> +             * Update RX descriptor with the physical address of the
>>> +             * new data buffer of the new allocated mbuf.
>>> +             */
>>> +            rxe->mbuf = nmb;
>>> +
>>> +            rxm->data_off = RTE_PKTMBUF_HEADROOM;
>>> +            rxdp->read.hdr_addr = dma;
>>> +            rxdp->read.pkt_addr = dma;
>>> +        } else
>>> +            rxe->mbuf = NULL;
>>> +
>>> +        /*
>>> +         * Set data length & data buffer address of mbuf.
>>> +         */
>>> +        data_len = rte_le_to_cpu_16(rxd.wb.upper.length);
>>> +        rxm->data_len = data_len;
>>> +
>>> +        if (!eop) {
>>> +            uint16_t nextp_id;
>>> +            /*
>>> +             * Get next descriptor index:
>>> +             *  - For RSC it's in the NEXTP field.
>>> +             *  - For a scattered packet - it's just a following
>>> +             *    descriptor.
>>> +             */
>>> +            if (ixgbe_rsc_count(&rxd))
>>> +                nextp_id =
>>> +                    (staterr & IXGBE_RXDADV_NEXTP_MASK) >>
>>> +                               IXGBE_RXDADV_NEXTP_SHIFT;
>>> +            else
>>> +                nextp_id = next_id;
>>> +
>>> +            next_rsc_entry = &sw_rsc_ring[nextp_id];
>>> +            next_rxe = &sw_ring[nextp_id];
>>> +            rte_ixgbe_prefetch(next_rxe);
>>> +        }
>>> +
>>> +        rsc_entry = &sw_rsc_ring[rx_id];
>>> +        first_seg = rsc_entry->fbuf;
>>> +        rsc_entry->fbuf = NULL;
>>> +
>>> +        /*
>>> +         * If this is the first buffer of the received packet,
>>> +         * set the pointer to the first mbuf of the packet and
>>> +         * initialize its context.
>>> +         * Otherwise, update the total length and the number of 
>>> segments
>>> +         * of the current scattered packet, and update the pointer to
>>> +         * the last mbuf of the current packet.
>>> +         */
>>> +        if (first_seg == NULL) {
>>> +            first_seg = rxm;
>>> +            first_seg->pkt_len = data_len;
>>> +            first_seg->nb_segs = 1;
>>> +        } else {
>>> +            first_seg->pkt_len += data_len;
>>> +            first_seg->nb_segs++;
>>> +        }
>>> +
>>> +        prev_id = rx_id;
>>> +        rx_id = next_id;
>>> +
>>> +        /*
>>> +         * If this is not the last buffer of the received packet, 
>>> update
>>> +         * the pointer to the first mbuf at the NEXTP entry in the
>>> +         * sw_rsc_ring and continue to parse the RX ring.
>>> +         */
>>> +        if (!eop) {
>>> +            rxm->next = next_rxe->mbuf;
>>> +            next_rsc_entry->fbuf = first_seg;
>>> +            goto next_desc;
>>> +        }
>>> +
>>> +        /*
>>> +         * This is the last buffer of the received packet - return
>>> +         * the current cluster to the user.
>>> +         */
>>> +        rxm->next = NULL;
>>> +
>>> +        /* Initialize the first mbuf of the returned packet */
>>> +        ixgbe_fill_cluster_head_buf(first_seg, &rxd, rxq->port_id,
>>> +                        staterr);
>>> +
>>> +        /* Prefetch data of first segment, if configured to do so. */
>>> +        rte_packet_prefetch((char *)first_seg->buf_addr +
>>> +            first_seg->data_off);
>>> +
>>> +        /*
>>> +         * Store the mbuf address into the next entry of the array
>>> +         * of returned packets.
>>> +         */
>>> +        rx_pkts[nb_rx++] = first_seg;
>>> +    }
>>> +
>>> +    /*
>>> +     * Record index of the next RX descriptor to probe.
>>> +     */
>>> +    rxq->rx_tail = rx_id;
>>> +
>>> +    /*
>>> +     * If the number of free RX descriptors is greater than the RX 
>>> free
>>> +     * threshold of the queue, advance the Receive Descriptor Tail 
>>> (RDT)
>>> +     * register.
>>> +     * Update the RDT with the value of the last processed RX 
>>> descriptor
>>> +     * minus 1, to guarantee that the RDT register is never equal 
>>> to the
>>> +     * RDH register, which creates a "full" ring situtation from the
>>> +     * hardware point of view...
>>> +     */
>>> +    if (!bulk_alloc && nb_hold > rxq->rx_free_thresh) {
>>> +        PMD_RX_LOG(DEBUG, "port_id=%u queue_id=%u rx_tail=%u "
>>> +               "nb_hold=%u nb_rx=%u",
>>> +               rxq->port_id, rxq->queue_id, rx_id, nb_hold, nb_rx);
>>> +
>>> +        rte_wmb();
>>> +        IXGBE_PCI_REG_WRITE(rxq->rdt_reg_addr, prev_id);
>>> +        nb_hold = 0;
>>> +    }
>>> +
>>> +    rxq->nb_rx_hold = nb_hold;
>>> +    return nb_rx;
>>> +}
>>> +
>>> +uint16_t
>>> +ixgbe_recv_pkts_lro_single_alloc(void *rx_queue, struct rte_mbuf 
>>> **rx_pkts,
>>> +                 uint16_t nb_pkts)
>>> +{
>>> +    return ixgbe_recv_pkts_lro(rx_queue, rx_pkts, nb_pkts, false);
>>> +}
>>> +
>>> +uint16_t
>>> +ixgbe_recv_pkts_lro_bulk_alloc(void *rx_queue, struct rte_mbuf 
>>> **rx_pkts,
>>> +                   uint16_t nb_pkts)
>>> +{
>>> +    return ixgbe_recv_pkts_lro(rx_queue, rx_pkts, nb_pkts, true);
>>> +}
>>> +
>>>   uint16_t
>>>   ixgbe_recv_scattered_pkts(void *rx_queue, struct rte_mbuf **rx_pkts,
>>>                 uint16_t nb_pkts)
>>> @@ -2005,6 +2295,31 @@ ixgbe_dev_tx_queue_setup(struct rte_eth_dev 
>>> *dev,
>>>       return (0);
>>>   }
>>>
>>> +/**
>>> + * ixgbe_free_rsc_cluster - free the not-yet-completed RSC cluster
>>> + *
>>> + * The "next" pointer of the last segment of (not-yet-completed) 
>>> RSC clusters
>>> + * in the sw_rsc_ring is not set to NULL but rather points to the next
>>> + * mbuf of this RSC aggregation (that has not been completed yet 
>>> and still
>>> + * resides on the HW ring). So, instead of calling for 
>>> rte_pktmbuf_free() we
>>> + * will just free first "nb_segs" segments of the cluster 
>>> explicitly by calling
>>> + * an rte_pktmbuf_free_seg().
>>> + *
>>> + * @m RSC cluster head
>>> + */
>>> +static void
>>> +ixgbe_free_rsc_cluster(struct rte_mbuf *m)
>>> +{
>>> +    uint8_t i, nb_segs = m->nb_segs;
>>> +    struct rte_mbuf *next_seg;
>>> +
>>> +    for (i = 0; i < nb_segs; i++) {
>>> +        next_seg = m->next;
>>> +        rte_pktmbuf_free_seg(m);
>>> +        m = next_seg;
>>> +    }
>>> +}
>>> +
>>>   static void
>>>   ixgbe_rx_queue_release_mbufs(struct ixgbe_rx_queue *rxq)
>>>   {
>>> @@ -2028,6 +2343,13 @@ ixgbe_rx_queue_release_mbufs(struct 
>>> ixgbe_rx_queue *rxq)
>>>           }
>>>   #endif
>>>       }
>>> +
>>> +    if (rxq->sw_rsc_ring)
>>> +        for (i = 0; i < rxq->nb_rx_desc; i++)
>>> +            if (rxq->sw_rsc_ring[i].fbuf) {
>>> + ixgbe_free_rsc_cluster(rxq->sw_rsc_ring[i].fbuf);
>>> +                rxq->sw_rsc_ring[i].fbuf = NULL;
>>> +            }
>>>   }
>>>
>>>   static void
>>> @@ -2036,6 +2358,7 @@ ixgbe_rx_queue_release(struct ixgbe_rx_queue 
>>> *rxq)
>>>       if (rxq != NULL) {
>>>           ixgbe_rx_queue_release_mbufs(rxq);
>>>           rte_free(rxq->sw_ring);
>>> +        rte_free(rxq->sw_rsc_ring);
>>>           rte_free(rxq);
>>>       }
>>>   }
>>> @@ -2158,6 +2481,7 @@ ixgbe_reset_rx_queue(struct ixgbe_hw *hw, 
>>> struct ixgbe_rx_queue *rxq)
>>>       rxq->nb_rx_hold = 0;
>>>       rxq->pkt_first_seg = NULL;
>>>       rxq->pkt_last_seg = NULL;
>>> +    rxq->rsc_en = 0;
>>>   }
>>>
>>>   int
>>> @@ -2172,6 +2496,14 @@ ixgbe_dev_rx_queue_setup(struct rte_eth_dev 
>>> *dev,
>>>       struct ixgbe_rx_queue *rxq;
>>>       struct ixgbe_hw     *hw;
>>>       uint16_t len;
>>> +    struct rte_eth_dev_info dev_info = { 0 };
>>> +    struct rte_eth_rxmode *dev_rx_mode = &dev->data->dev_conf.rxmode;
>>> +    bool rsc_requested = false;
>>> +
>>> +    dev->dev_ops->dev_infos_get(dev, &dev_info);
>>> +    if ((dev_info.rx_offload_capa & DEV_RX_OFFLOAD_TCP_LRO) &&
>>> +        dev_rx_mode->enable_lro)
>>> +        rsc_requested = true;
>>>
>>>       PMD_INIT_FUNC_TRACE();
>>>       hw = IXGBE_DEV_PRIVATE_TO_HW(dev->data->dev_private);
>>> @@ -2277,12 +2609,27 @@ ixgbe_dev_rx_queue_setup(struct rte_eth_dev 
>>> *dev,
>>>       rxq->sw_ring = rte_zmalloc_socket("rxq->sw_ring",
>>>                         sizeof(struct ixgbe_rx_entry) * len,
>>>                         RTE_CACHE_LINE_SIZE, socket_id);
>>> -    if (rxq->sw_ring == NULL) {
>>> +    if (!rxq->sw_ring) {
>>>           ixgbe_rx_queue_release(rxq);
>>>           return (-ENOMEM);
>>>       }
>>> -    PMD_INIT_LOG(DEBUG, "sw_ring=%p hw_ring=%p dma_addr=0x%"PRIx64,
>>> -             rxq->sw_ring, rxq->rx_ring, rxq->rx_ring_phys_addr);
>>> +
>>> +    if (rsc_requested) {
>>> +        rxq->sw_rsc_ring =
>>> +            rte_zmalloc_socket("rxq->sw_rsc_ring",
>>> +                       sizeof(struct ixgbe_rsc_entry) * len,
>>> +                       RTE_CACHE_LINE_SIZE, socket_id);
>>> +        if (!rxq->sw_rsc_ring) {
>>> +            ixgbe_rx_queue_release(rxq);
>>> +            return (-ENOMEM);
>>> +        }
>>> +    } else
>>> +        rxq->sw_rsc_ring = NULL;
>>> +
>>> +    PMD_INIT_LOG(DEBUG, "sw_ring=%p sw_rsc_ring=%p hw_ring=%p "
>>> +                "dma_addr=0x%"PRIx64,
>>> +             rxq->sw_ring, rxq->sw_rsc_ring, rxq->rx_ring,
>>> +             rxq->rx_ring_phys_addr);
>>>
>>>       if (!rte_is_power_of_2(nb_desc)) {
>>>           PMD_INIT_LOG(DEBUG, "queue[%d] doesn't meet Vector Rx "
>>> @@ -3527,6 +3874,91 @@ ixgbe_dev_mq_tx_configure(struct rte_eth_dev 
>>> *dev)
>>>       return 0;
>>>   }
>>>
>>> +/**
>>> + * ixgbe_get_rscctl_maxdesc - Calculate the RSCCTL[n].MAXDESC for PF
>>> + *
>>> + * Return the RSCCTL[n].MAXDESC for 82599 and x540 PF devices 
>>> according to the
>>> + * spec rev. 3.0 chapter 8.2.3.8.13.
>>> + *
>>> + * @pool Memory pool of the Rx queue
>>> + */
>>> +static inline uint32_t
>>> +ixgbe_get_rscctl_maxdesc(struct rte_mempool *pool)
>>> +{
>>> +    struct rte_pktmbuf_pool_private *mp_priv = 
>>> rte_mempool_get_priv(pool);
>>> +
>>> +    /* MAXDESC * SRRCTL.BSIZEPKT must not exceed 64 KB minus one */
>>> +    uint16_t maxdesc =
>>> +        IPV4_MAX_PKT_LEN /
>>> +            (mp_priv->mbuf_data_room_size - RTE_PKTMBUF_HEADROOM);
>>> +
>>> +    if (maxdesc >= 16)
>>> +        return IXGBE_RSCCTL_MAXDESC_16;
>>> +    else if (maxdesc >= 8)
>>> +        return IXGBE_RSCCTL_MAXDESC_8;
>>> +    else if (maxdesc >= 4)
>>> +        return IXGBE_RSCCTL_MAXDESC_4;
>>> +    else
>>> +        return IXGBE_RSCCTL_MAXDESC_1;
>>> +}
>>> +
>>> +/**
>>> + * ixgbe_set_ivar - Setup the correct IVAR register for a 
>>> particular MSIX
>>> + * interrupt
>>> + *
>>> + * (Taken from FreeBSD tree)
>>> + * (yes this is all very magic and confusing :)
>>> + *
>>> + * @dev port handle
>>> + * @entry the register array entry
>>> + * @vector the MSIX vector for this queue
>>> + * @type RX/TX/MISC
>>> + */
>>> +static void
>>> +ixgbe_set_ivar(struct rte_eth_dev *dev, u8 entry, u8 vector, s8 type)
>>> +{
>>> +    struct ixgbe_hw *hw = 
>>> IXGBE_DEV_PRIVATE_TO_HW(dev->data->dev_private);
>>> +    u32 ivar, index;
>>> +
>>> +    vector |= IXGBE_IVAR_ALLOC_VAL;
>>> +
>>> +    switch (hw->mac.type) {
>>> +
>>> +    case ixgbe_mac_82598EB:
>>> +        if (type == -1)
>>> +            entry = IXGBE_IVAR_OTHER_CAUSES_INDEX;
>>> +        else
>>> +            entry += (type * 64);
>>> +        index = (entry >> 2) & 0x1F;
>>> +        ivar = IXGBE_READ_REG(hw, IXGBE_IVAR(index));
>>> +        ivar &= ~(0xFF << (8 * (entry & 0x3)));
>>> +        ivar |= (vector << (8 * (entry & 0x3)));
>>> +        IXGBE_WRITE_REG(hw, IXGBE_IVAR(index), ivar);
>>> +        break;
>>> +
>>> +    case ixgbe_mac_82599EB:
>>> +    case ixgbe_mac_X540:
>>> +        if (type == -1) { /* MISC IVAR */
>>> +            index = (entry & 1) * 8;
>>> +            ivar = IXGBE_READ_REG(hw, IXGBE_IVAR_MISC);
>>> +            ivar &= ~(0xFF << index);
>>> +            ivar |= (vector << index);
>>> +            IXGBE_WRITE_REG(hw, IXGBE_IVAR_MISC, ivar);
>>> +        } else {    /* RX/TX IVARS */
>>> +            index = (16 * (entry & 1)) + (8 * type);
>>> +            ivar = IXGBE_READ_REG(hw, IXGBE_IVAR(entry >> 1));
>>> +            ivar &= ~(0xFF << index);
>>> +            ivar |= (vector << index);
>>> +            IXGBE_WRITE_REG(hw, IXGBE_IVAR(entry >> 1), ivar);
>>> +        }
>>> +
>>> +        break;
>>> +
>>> +    default:
>>> +        break;
>>> +    }
>>> +}
>>> +
>>>   void ixgbe_set_rx_function(struct rte_eth_dev *dev)
>>>   {
>>>       struct ixgbe_hw *hw = 
>>> IXGBE_DEV_PRIVATE_TO_HW(dev->data->dev_private);
>>> @@ -3545,7 +3977,24 @@ void ixgbe_set_rx_function(struct rte_eth_dev 
>>> *dev)
>>>           hw->rx_vec_allowed = false;
>>>       }
>>>
>>> -    if (dev->data->scattered_rx) {
>>> +    /*
>>> +     * Initialize the appropriate LRO callback.
>>> +     *
>>> +     * If all queues satisfy the bulk allocation preconditions
>>> +     * (hw->rx_bulk_alloc_allowed is TRUE) then we may use bulk 
>>> allocation.
>>> +     * Otherwise use a single allocation version.
>>> +     */
>>> +    if (dev->data->lro) {
>>> +        if (hw->rx_bulk_alloc_allowed) {
>>> +            PMD_INIT_LOG(INFO, "LRO is requested. Using a bulk "
>>> +                       "allocation version");
>>> +            dev->rx_pkt_burst = ixgbe_recv_pkts_lro_bulk_alloc;
>>> +        } else {
>>> +            PMD_INIT_LOG(INFO, "LRO is requested. Using a single "
>>> +                       "allocation version");
>>> +            dev->rx_pkt_burst = ixgbe_recv_pkts_lro_single_alloc;
>>> +        }
>>> +    } else if (dev->data->scattered_rx) {
>>>           /*
>>>            * Set the non-LRO scattered callback: there are Vector and
>>>            * single allocation versions.
>>> @@ -3595,6 +4044,149 @@ void ixgbe_set_rx_function(struct 
>>> rte_eth_dev *dev)
>>>       }
>>>   }
>>>
>>> +/**
>>> + * ixgbe_set_rsc - configure RSC related port HW registers
>>> + *
>>> + * Configures the port's RSC related registers according to the 
>>> 4.6.7.2 chapter
>>> + * of 82599 Spec (x540 configuration is virtually the same).
>>> + *
>>> + * @dev port handle
>>> + *
>>> + * Returns 0 in case of success or a non-zero error code
>>> + */
>>> +static int
>>> +ixgbe_set_rsc(struct rte_eth_dev *dev)
>>> +{
>>> +    struct rte_eth_rxmode *rx_conf = &dev->data->dev_conf.rxmode;
>>> +    struct ixgbe_hw *hw = 
>>> IXGBE_DEV_PRIVATE_TO_HW(dev->data->dev_private);
>>> +    struct rte_eth_dev_info dev_info = { 0 };
>>> +    bool rsc_capable = false;
>>> +    uint16_t i;
>>> +    uint32_t rdrxctl;
>>> +
>>> +    /* Sanity check */
>>> +    dev->dev_ops->dev_infos_get(dev, &dev_info);
>>> +    if (dev_info.rx_offload_capa & DEV_RX_OFFLOAD_TCP_LRO)
>>> +        rsc_capable = true;
>>> +
>>> +    if (!rsc_capable && rx_conf->enable_lro) {
>>> +        PMD_INIT_LOG(CRIT, "LRO is requested on HW that doesn't "
>>> +                   "support it");
>>> +        return -EINVAL;
>>> +    }
>>> +
>>> +    /* RSC global configuration (chapter 4.6.7.2.1 of 82599 Spec) */
>>> +
>>> +    if (!rx_conf->hw_strip_crc && rx_conf->enable_lro) {
>>> +        /*
>>> +         * According to chapter of 4.6.7.2.1 of the Spec Rev.
>>> +         * 3.0 RSC configuration requires HW CRC stripping being
>>> +         * enabled. If user requested both HW CRC stripping off
>>> +         * and RSC on - return an error.
>>> +         */
>>> +        PMD_INIT_LOG(CRIT, "LRO can't be enabled when HW CRC "
>>> +                    "is disabled");
>>> +        return -EINVAL;
>>> +    }
>>> +
>>> +    /* RFCTL configuration  */
>>> +    if (rsc_capable) {
>>> +        uint32_t rfctl = IXGBE_READ_REG(hw, IXGBE_RFCTL);
>>> +        if (rx_conf->enable_lro)
>>> +            /*
>>> +             * Since NFS packets coalescing is not supported - clear
>>> +             * RFCTL.NFSW_DIS and RFCTL.NFSR_DIS when RSC is
>>> +             * enabled.
>>> +             */
>>> +            rfctl &= ~(IXGBE_RFCTL_RSC_DIS | IXGBE_RFCTL_NFSW_DIS |
>>> +                   IXGBE_RFCTL_NFSR_DIS);
>>> +        else
>>> +            rfctl |= IXGBE_RFCTL_RSC_DIS;
>>> +
>>> +        IXGBE_WRITE_REG(hw, IXGBE_RFCTL, rfctl);
>>> +    }
>>> +
>>> +    /* If LRO hasn't been requested - we are done here. */
>>> +    if (!rx_conf->enable_lro)
>>> +        return 0;
>>> +
>>> +    /* Set RDRXCTL.RSCACKC bit */
>>> +    rdrxctl = IXGBE_READ_REG(hw, IXGBE_RDRXCTL);
>>> +    rdrxctl |= IXGBE_RDRXCTL_RSCACKC;
>>> +    IXGBE_WRITE_REG(hw, IXGBE_RDRXCTL, rdrxctl);
>>> +
>>> +    /* Per-queue RSC configuration (chapter 4.6.7.2.2 of 82599 
>>> Spec) */
>>> +    for (i = 0; i < dev->data->nb_rx_queues; i++) {
>>> +        struct ixgbe_rx_queue *rxq = dev->data->rx_queues[i];
>>> +        uint32_t srrctl =
>>> +            IXGBE_READ_REG(hw, IXGBE_SRRCTL(rxq->reg_idx));
>>> +        uint32_t rscctl =
>>> +            IXGBE_READ_REG(hw, IXGBE_RSCCTL(rxq->reg_idx));
>>> +        uint32_t psrtype =
>>> +            IXGBE_READ_REG(hw, IXGBE_PSRTYPE(rxq->reg_idx));
>>> +        uint32_t eitr =
>>> +            IXGBE_READ_REG(hw, IXGBE_EITR(rxq->reg_idx));
>>> +
>>> +        /*
>>> +         * ixgbe PMD doesn't support header-split at the moment.
>>> +         *
>>> +         * Following the 4.6.7.2.1 chapter of the 82599/x540
>>> +         * Spec if RSC is enabled the SRRCTL[n].BSIZEHEADER
>>> +         * should be configured even if header split is not
>>> +         * enabled. We will configure it 128 bytes following the
>>> +         * recommendation in the spec.
>>> +         */
>>> +        srrctl &= ~IXGBE_SRRCTL_BSIZEHDR_MASK;
>>> +        srrctl |= (128 << IXGBE_SRRCTL_BSIZEHDRSIZE_SHIFT) &
>>> +                        IXGBE_SRRCTL_BSIZEHDR_MASK;
>>> +
>>> +        /*
>>> +         * TODO: Consider setting the Receive Descriptor Minimum
>>> +         * Threshold Size for an RSC case. This is not an obviously
>>> +         * beneficiary option but the one worth considering...
>>> +         */
>>> +
>>> +        rscctl |= IXGBE_RSCCTL_RSCEN;
>>> +        rscctl |= ixgbe_get_rscctl_maxdesc(rxq->mb_pool);
>>> +        psrtype |= IXGBE_PSRTYPE_TCPHDR;
>>> +
>>> +        /*
>>> +         * RSC: Set ITR interval corresponding to 2K ints/s.
>>> +         *
>>> +         * Full-sized RSC aggregations for a 10Gb/s link will
>>> +         * arrive at about 20K aggregation/s rate.
>>> +         *
>>> +         * 2K inst/s rate will make only 10% of the
>>> +         * aggregations to be closed due to the interrupt timer
>>> +         * expiration for a streaming at wire-speed case.
>>> +         *
>>> +         * For a sparse streaming case this setting will yield
>>> +         * at most 500us latency for a single RSC aggregation.
>>> +         */
>>> +        eitr &= ~IXGBE_EITR_ITR_INT_MASK;
>>> +        eitr |= IXGBE_EITR_INTERVAL_US(500) | IXGBE_EITR_CNT_WDIS;
>>> +
>>> +        IXGBE_WRITE_REG(hw, IXGBE_SRRCTL(rxq->reg_idx), srrctl);
>>> +        IXGBE_WRITE_REG(hw, IXGBE_RSCCTL(rxq->reg_idx), rscctl);
>>> +        IXGBE_WRITE_REG(hw, IXGBE_PSRTYPE(rxq->reg_idx), psrtype);
>>> +        IXGBE_WRITE_REG(hw, IXGBE_EITR(rxq->reg_idx), eitr);
>>> +
>>> +        /*
>>> +         * RSC requires the mapping of the queue to the
>>> +         * interrupt vector.
>>> +         */
>>> +        ixgbe_set_ivar(dev, rxq->reg_idx, i, 0);
>>> +
>>> +        rxq->rsc_en = 1;
>>> +    }
>>> +
>>> +    dev->data->lro = 1;
>>> +
>>> +    PMD_INIT_LOG(INFO, "enabling LRO mode");
>>> +
>>> +    return 0;
>>> +}
>>> +
>>>   /*
>>>    * Initializes Receive Unit.
>>>    */
>>> @@ -3615,6 +4207,7 @@ ixgbe_dev_rx_init(struct rte_eth_dev *dev)
>>>       uint16_t buf_size;
>>>       uint16_t i;
>>>       struct rte_eth_rxmode *rx_conf = &dev->data->dev_conf.rxmode;
>>> +    int rc;
>>>
>>>       PMD_INIT_FUNC_TRACE();
>>>       hw = IXGBE_DEV_PRIVATE_TO_HW(dev->data->dev_private);
>>> @@ -3724,6 +4317,7 @@ ixgbe_dev_rx_init(struct rte_eth_dev *dev)
>>>                          RTE_PKTMBUF_HEADROOM);
>>>           srrctl |= ((buf_size >> IXGBE_SRRCTL_BSIZEPKT_SHIFT) &
>>>                  IXGBE_SRRCTL_BSIZEPKT_MASK);
>>> +
>>>           IXGBE_WRITE_REG(hw, IXGBE_SRRCTL(rxq->reg_idx), srrctl);
>>>
>>>           buf_size = (uint16_t) ((srrctl & 
>>> IXGBE_SRRCTL_BSIZEPKT_MASK) <<
>>> @@ -3738,8 +4332,6 @@ ixgbe_dev_rx_init(struct rte_eth_dev *dev)
>>>       if (rx_conf->enable_scatter)
>>>           dev->data->scattered_rx = 1;
>>>
>>> -    ixgbe_set_rx_function(dev);
>>> -
>>>       /*
>>>        * Device configured with multiple RX queues.
>>>        */
>>> @@ -3770,6 +4362,12 @@ ixgbe_dev_rx_init(struct rte_eth_dev *dev)
>>>           IXGBE_WRITE_REG(hw, IXGBE_RDRXCTL, rdrxctl);
>>>       }
>>>
>>> +    rc = ixgbe_set_rsc(dev);
>>> +    if (rc)
>>> +        return rc;
>>> +
>>> +    ixgbe_set_rx_function(dev);
>>> +
>>>       return 0;
>>>   }
>>>
>>> diff --git a/lib/librte_pmd_ixgbe/ixgbe_rxtx.h 
>>> b/lib/librte_pmd_ixgbe/ixgbe_rxtx.h
>>> index 3937cf6..120bbbd 100644
>>> --- a/lib/librte_pmd_ixgbe/ixgbe_rxtx.h
>>> +++ b/lib/librte_pmd_ixgbe/ixgbe_rxtx.h
>>> @@ -79,6 +79,10 @@ struct ixgbe_rx_entry {
>>>       struct rte_mbuf *mbuf; /**< mbuf associated with RX 
>>> descriptor. */
>>>   };
>>>
>>> +struct ixgbe_rsc_entry {
>>> +    struct rte_mbuf *fbuf; /**< First segment of the fragmented 
>>> packet. */
>>> +};
>>> +
>>>   /**
>>>    * Structure associated with each descriptor of the TX ring of a 
>>> TX queue.
>>>    */
>>> @@ -105,6 +109,7 @@ struct ixgbe_rx_queue {
>>>       volatile uint32_t   *rdt_reg_addr; /**< RDT register address. */
>>>       volatile uint32_t   *rdh_reg_addr; /**< RDH register address. */
>>>       struct ixgbe_rx_entry *sw_ring; /**< address of RX software 
>>> ring. */
>>> +    struct ixgbe_rsc_entry *sw_rsc_ring; /**< address of RSC 
>>> software ring. */
>>>       struct rte_mbuf *pkt_first_seg; /**< First segment of current 
>>> packet. */
>>>       struct rte_mbuf *pkt_last_seg; /**< Last segment of current 
>>> packet. */
>>>       uint64_t            mbuf_initializer; /**< value to init mbufs */
>>> @@ -126,6 +131,7 @@ struct ixgbe_rx_queue {
>>>       uint8_t             port_id;  /**< Device port identifier. */
>>>       uint8_t             crc_len;  /**< 0 if CRC stripped, 4 
>>> otherwise. */
>>>       uint8_t             drop_en;  /**< If not 0, set 
>>> SRRCTL.Drop_En. */
>>> +    uint8_t             rsc_en;   /**< If not 0, RSC is enabled. */
>>>       uint8_t             rx_deferred_start; /**< not in global dev 
>>> start. */
>>>   #ifdef RTE_LIBRTE_IXGBE_RX_ALLOW_BULK_ALLOC
>>>       /** need to alloc dummy mbuf, for wraparound when scanning hw 
>>> ring */
>>> -- 
>>> 2.1.0
>