ibv_create_cq_ex — create a completion queue (CQ)
Synopsis
#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
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 */
};
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,
};
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
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.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
ibv_create_cq_ex() returns a pointer to the CQ, or NULL if the request fails.
Notes
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
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)
Referenced By
mlx5dv_create_cq(3), mlx5dv_create_flow(3).