ibv_create_cq_ex(3) — Linux manual page

NAME | SYNOPSIS | DESCRIPTION | Polling an extended CQ | RETURN VALUE | NOTES | SEE ALSO | AUTHORS | COLOPHON

IBV_CREATE_CQ_EX(3)  Libibverbs Programmer's Manual  IBV_CREATE_CQ_EX(3)

NAME         top

       ibv_create_cq_ex - create a completion queue (CQ)

SYNOPSIS         top

       #include <infiniband/verbs.h>

       struct ibv_cq_ex *ibv_create_cq_ex(struct ibv_context *context,
                                          struct ibv_cq_init_attr_ex *cq_attr);

DESCRIPTION         top

       ibv_create_cq_ex() creates a completion queue (CQ) for RDMA
       device context context.  The argument cq_attr is a pointer to
       struct ibv_cq_init_attr_ex as defined in <infiniband/verbs.h>.

       struct ibv_cq_init_attr_ex {
               int                     cqe;               /* Minimum number of entries required for CQ */
               void                    *cq_context;       /* Consumer-supplied context returned for completion events */
               struct ibv_comp_channel *channel;          /* Completion channel where completion events will be queued. May be NULL if completion events will not be used. */
               int                     comp_vector;       /* Completion vector used to signal completion events. Must be >= 0 and < context->num_comp_vectors. */
               uint64_t                wc_flags;          /* The wc_flags that should be returned in ibv_poll_cq_ex. Or'ed bit of enum ibv_wc_flags_ex. */
               uint32_t                comp_mask;         /* compatibility mask (extended verb). */
               uint32_t                flags              /* One or more flags from enum ibv_create_cq_attr_flags */
               struct ibv_pd           *parent_domain;    /* Parent domain to be used by this CQ */
       };

       enum ibv_wc_flags_ex {
               IBV_WC_EX_WITH_BYTE_LEN              = 1 << 0,  /* Require byte len in WC */
               IBV_WC_EX_WITH_IMM                   = 1 << 1,  /* Require immediate in WC */
               IBV_WC_EX_WITH_QP_NUM                = 1 << 2,  /* Require QP number in WC */
               IBV_WC_EX_WITH_SRC_QP                = 1 << 3,  /* Require source QP in WC */
               IBV_WC_EX_WITH_SLID                  = 1 << 4,  /* Require slid in WC */
               IBV_WC_EX_WITH_SL                    = 1 << 5,  /* Require sl in WC */
               IBV_WC_EX_WITH_DLID_PATH_BITS        = 1 << 6,  /* Require dlid path bits in WC */
               IBV_WC_EX_WITH_COMPLETION_TIMESTAMP  = 1 << 7,  /* Require completion device timestamp in WC /*
               IBV_WC_EX_WITH_CVLAN                 = 1 << 8,  /* Require VLAN info in WC */
               IBV_WC_EX_WITH_FLOW_TAG              = 1 << 9,  /* Require flow tag in WC */
               IBV_WC_EX_WITH_COMPLETION_TIMESTAMP_WALLCLOCK  = 1 << 11, /* Require completion wallclock timestamp in WC */
       };

       enum ibv_cq_init_attr_mask {
               IBV_CQ_INIT_ATTR_MASK_FLAGS             = 1 << 0,
               IBV_CQ_INIT_ATTR_MASK_PD                = 1 << 1,
       };

       enum ibv_create_cq_attr_flags {
               IBV_CREATE_CQ_ATTR_SINGLE_THREADED      = 1 << 0, /* This CQ is used from a single threaded, thus no locking is required */
               IBV_CREATE_CQ_ATTR_IGNORE_OVERRUN       = 1 << 1, /* This CQ will not pass to error state if overrun, CQE always will be written to next entry.
                                                                  * An application must be designed to avoid ever overflowing the CQ, otherwise CQEs might be lost.
                                                                  */
       };

Polling an extended CQ         top

       In order to poll an extended CQ efficiently, a user could use the
       following functions.

       Completion iterator functions

              int ibv_start_poll(struct ibv_cq_ex *cq, struct
              ibv_poll_cq_attr *attr)
              Start polling a batch of work completions.  attr is given
              in order to make this function easily extensible in the
              future. This function either returns 0 on success or an
              error code otherwise. When no completions are available on
              the CQ, ENOENT is returned, but the CQ remains in a valid
              state. On success, querying the completion's attribute
              could be done using the query functions described below.
              If an error code is given, end_poll shouldn't be called.

              int ibv_next_poll(struct ibv_cq_ex *cq)
              This function is called in order to get the next work
              completion. It has to be called after start_poll and
              before end_poll are called. This function either returns 0
              on success or an error code otherwise. When no completions
              are available on the CQ, ENOENT is returned, but the CQ
              remains in a valid state. On success, querying the
              completion's attribute could be done using the query
              functions described below. If an error code is given,
              end_poll should still be called, indicating this is the
              end of the polled batch.

              void ibv_end_poll(struct ibv_cq_ex *cq)
              This function indicates the end of polling batch of work
              completions. After calling this function, the user should
              start a new batch by calling start_poll.

       Polling fields in the completion
              Below members and functions are used in order to poll the
              current completion. The current completion is the
              completion which the iterator points to (start_poll and
              next_poll advances this iterator). Only fields that the
              user requested via wc_flags in ibv_create_cq_ex could be
              queried. In addition, some fields are only valid in
              certain opcodes and status codes.

              uint64_t wr_id - Can be accessed directly from struct
              ibv_cq_ex.

              enum ibv_wc_status - Can be accessed directly from struct
              ibv_cq_ex.

              enum ibv_wc_opcode ibv_wc_read_opcode(struct ibv_cq_ex
              *cq); Get the opcode from the current completion.

              uint32_t ibv_wc_read_vendor_err(struct ibv_cq_ex *cq); Get
              the vendor error from the current completion.

              uint32_t ibv_wc_read_byte_len(struct ibv_cq_ex *cq); Get
              the vendor error from the current completion.

              __be32 ibv_wc_read_imm_data(struct ibv_cq_ex *cq); Get the
              immediate data field from the current completion.

              uint32_t ibv_wc_read_invalidated_rkey(struct ibv_cq_ex
              *cq); Get the rkey invalided by the SEND_INVAL from the
              current completion.

              uint32_t ibv_wc_read_qp_num(struct ibv_cq_ex *cq); Get the
              QP number field from the current completion.

              uint32_t ibv_wc_read_src_qp(struct ibv_cq_ex *cq); Get the
              source QP number field from the current completion.

              unsigned int ibv_wc_read_wc_flags(struct ibv_cq_ex *cq);
              Get the QP flags field from the current completion.

              uint16_t ibv_wc_read_pkey_index(struct ibv_cq_ex *cq); Get
              the pkey index field from the current completion.

              uint32_t ibv_wc_read_slid(struct ibv_cq_ex *cq); Get the
              slid field from the current completion.

              uint8_t ibv_wc_read_sl(struct ibv_cq_ex *cq); Get the sl
              field from the current completion.

              uint8_t ibv_wc_read_dlid_path_bits(struct ibv_cq_ex *cq);
              Get the dlid_path_bits field from the current completion.

              uint64_t ibv_wc_read_completion_ts(struct ibv_cq_ex *cq);
              Get the completion timestamp from the current completion
              in HCA clock units.

              uint64_t ibv_wc_read_completion_wallclock_ns(struct
              ibv_cq_ex *cq); Get the completion timestamp from the
              current completion and convert it from HCA clock units to
              wall clock nanoseconds.

              uint16_t ibv_wc_read_cvlan(struct ibv_cq_ex *cq); Get the
              CVLAN field from the current completion.

              uint32_t ibv_wc_read_flow_tag(struct ibv_cq_ex *cq); Get
              flow tag from the current completion.

              void ibv_wc_read_tm_info(struct ibv_cq_ex *cq, struct
              ibv_wc_tm_info *tm_info);  Get tag matching info from the
              current completion.
              struct ibv_wc_tm_info {
                      uint64_t tag;  /* tag from TMH */
                      uint32_t priv; /* opaque user data from TMH */
              };

RETURN VALUE         top

       ibv_create_cq_ex() returns a pointer to the CQ, or NULL if the
       request fails.

NOTES         top

       ibv_create_cq_ex() may create a CQ with size greater than or
       equal to the requested size. Check the cqe attribute in the
       returned CQ for the actual size.

       CQ should be destroyed with ibv_destroy_cq.

SEE ALSO         top

       ibv_create_cq(3), ibv_destroy_cq(3), ibv_resize_cq(3),
       ibv_req_notify_cq(3), ibv_ack_cq_events(3), ibv_create_qp(3),
       ibv_alloc_parent_domain(3)

AUTHORS         top

       Matan Barak <matanb@mellanox.com>

COLOPHON         top

       This page is part of the rdma-core (RDMA Core Userspace Libraries
       and Daemons) project.  Information about the project can be found
       at ⟨https://github.com/linux-rdma/rdma-core⟩.  If you have a bug
       report for this manual page, send it to
       linux-rdma@vger.kernel.org.  This page was obtained from the
       project's upstream Git repository
       ⟨https://github.com/linux-rdma/rdma-core.git⟩ on 2021-08-27.  (At
       that time, the date of the most recent commit that was found in
       the repository was 2021-08-18.)  If you discover any rendering
       problems in this HTML version of the page, or you believe there
       is a better or more up-to-date source for the page, or you have
       corrections or improvements to the information in this COLOPHON
       (which is not part of the original manual page), send a mail to
       man-pages@man7.org

libibverbs                     2016-05-08            IBV_CREATE_CQ_EX(3)