1IBV_CREATE_CQ_EX(3)     Libibverbs Programmer's Manual     IBV_CREATE_CQ_EX(3)
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NAME

6       ibv_create_cq_ex - create a completion queue (CQ)
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SYNOPSIS

9       #include <infiniband/verbs.h>
10
11       struct ibv_cq_ex *ibv_create_cq_ex(struct ibv_context *context,
12                                          struct ibv_cq_init_attr_ex *cq_attr);
13

DESCRIPTION

15       ibv_create_cq_ex() creates a completion queue (CQ) for RDMA device con‐
16       text  context.   The  argument  cq_attr  is   a   pointer   to   struct
17       ibv_cq_init_attr_ex as defined in <infiniband/verbs.h>.
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19       struct ibv_cq_init_attr_ex {
20               int                     cqe;               /* Minimum number of entries required for CQ */
21               void                    *cq_context;       /* Consumer-supplied context returned for completion events */
22               struct ibv_comp_channel *channel;          /* Completion channel where completion events will be queued. May be NULL if completion events will not be used. */
23               int                     comp_vector;       /* Completion vector used to signal completion events. Must be >= 0 and < context->num_comp_vectors. */
24               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. */
25               uint32_t                comp_mask;         /* compatibility mask (extended verb). */
26               uint32_t                flags              /* One or more flags from enum ibv_create_cq_attr_flags */
27       };
28
29       enum ibv_wc_flags_ex {
30               IBV_WC_EX_WITH_BYTE_LEN              = 1 << 0,  /* Require byte len in WC */
31               IBV_WC_EX_WITH_IMM                   = 1 << 1,  /* Require immediate in WC */
32               IBV_WC_EX_WITH_QP_NUM                = 1 << 2,  /* Require QP number in WC */
33               IBV_WC_EX_WITH_SRC_QP                = 1 << 3,  /* Require source QP in WC */
34               IBV_WC_EX_WITH_SLID                  = 1 << 4,  /* Require slid in WC */
35               IBV_WC_EX_WITH_SL                    = 1 << 5,  /* Require sl in WC */
36               IBV_WC_EX_WITH_DLID_PATH_BITS        = 1 << 6,  /* Require dlid path bits in WC */
37               IBV_WC_EX_WITH_COMPLETION_TIMESTAMP  = 1 << 7,  /* Require completion device timestamp in WC /*
38               IBV_WC_EX_WITH_CVLAN                 = 1 << 8,  /* Require VLAN info in WC */
39               IBV_WC_EX_WITH_FLOW_TAG              = 1 << 9,  /* Require flow tag in WC */
40               IBV_WC_EX_WITH_COMPLETION_TIMESTAMP_WALLCLOCK  = 1 << 11, /* Require completion wallclock timestamp in WC */
41       };
42
43       enum ibv_cq_init_attr_mask {
44               IBV_CQ_INIT_ATTR_MASK_FLAGS             = 1 << 0,
45       };
46
47       enum ibv_create_cq_attr_flags {
48               IBV_CREATE_CQ_ATTR_SINGLE_THREADED      = 1 << 0, /* This CQ is used from a single threaded, thus no locking is required */
49               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.
50                                                                  * An application must be designed to avoid ever overflowing the CQ, otherwise CQEs might be lost.
51                                                                  */
52       };
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54

Polling an extended CQ

56       In  order to poll an extended CQ efficiently, a user could use the fol‐
57       lowing functions.
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59
60       Completion iterator functions
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62              int ibv_start_poll(struct ibv_cq_ex *cq, struct ibv_poll_cq_attr
63              *attr)
64              Start  polling  a  batch  of work completions.  attr is given in
65              order to make this function easily  extensible  in  the  future.
66              This  function either returns 0 on success or an error code oth‐
67              erwise. When no completions are available on the CQ,  ENOENT  is
68              returned,  but  the  CQ  remains  in  a valid state. On success,
69              querying the completion's attribute  could  be  done  using  the
70              query  functions  described  below.  If  an error code is given,
71              end_poll shouldn't be called.
72
73              int ibv_next_poll(struct ibv_cq_ex *cq)
74              This function is called in order to get the  next  work  comple‐
75              tion.  It  has to be called after start_poll and before end_poll
76              are called. This function either returns  0  on  success  or  an
77              error  code  otherwise. When no completions are available on the
78              CQ, ENOENT is returned, but the CQ remains in a valid state.  On
79              success, querying the completion's attribute could be done using
80              the query functions described below. If an error code is  given,
81              end_poll  should  still be called, indicating this is the end of
82              the polled batch.
83
84              void ibv_end_poll(struct ibv_cq_ex *cq)
85              This function indicates the end of polling batch of work comple‐
86              tions.  After calling this function, the user should start a new
87              batch by calling start_poll.
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89
90       Polling fields in the completion
91              Below members and functions are used in order to poll  the  cur‐
92              rent  completion. The current completion is the completion which
93              the iterator points to (start_poll and next_poll  advances  this
94              iterator).  Only  fields that the user requested via wc_flags in
95              ibv_create_cq_ex could be queried. In addition, some fields  are
96              only valid in certain opcodes and status codes.
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98              uint64_t wr_id - Can be accessed directly from struct ibv_cq_ex.
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100              enum  ibv_wc_status  -  Can  be  accessed  directly  from struct
101              ibv_cq_ex.
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103              enum ibv_wc_opcode ibv_wc_read_opcode(struct ibv_cq_ex *cq); Get
104              the opcode from the current completion.
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106              uint32_t  ibv_wc_read_vendor_err(struct  ibv_cq_ex *cq); Get the
107              vendor error from the current completion.
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109              uint32_t ibv_wc_read_byte_len(struct  ibv_cq_ex  *cq);  Get  the
110              vendor error from the current completion.
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112              __be32 ibv_wc_read_imm_data(struct ibv_cq_ex *cq); Get the imme‐
113              diate data field from the current completion.
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115              uint32_t ibv_wc_read_invalidated_rkey(struct ibv_cq_ex *cq); Get
116              the  rkey  invalided  by the SEND_INVAL from the current comple‐
117              tion.
118
119              uint32_t ibv_wc_read_qp_num(struct ibv_cq_ex *cq);  Get  the  QP
120              number field from the current completion.
121
122              uint32_t   ibv_wc_read_src_qp(struct  ibv_cq_ex  *cq);  Get  the
123              source QP number field from the current completion.
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125              int ibv_wc_read_wc_flags(struct ibv_cq_ex *cq); Get the QP flags
126              field from the current completion.
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128              uint16_t  ibv_wc_read_pkey_index(struct  ibv_cq_ex *cq); Get the
129              pkey index field from the current completion.
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131              uint32_t ibv_wc_read_slid(struct ibv_cq_ex *cq);  Get  the  slid
132              field from the current completion.
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134              uint8_t  ibv_wc_read_sl(struct  ibv_cq_ex *cq); Get the sl field
135              from the current completion.
136
137              uint8_t ibv_wc_read_dlid_path_bits(struct  ibv_cq_ex  *cq);  Get
138              the dlid_path_bits field from the current completion.
139
140              uint64_t  ibv_wc_read_completion_ts(struct  ibv_cq_ex  *cq); Get
141              the completion timestamp from  the  current  completion  in  HCA
142              clock units.
143
144              uint64_t   ibv_wc_read_completion_wallclock_ns(struct  ibv_cq_ex
145              *cq); Get the completion timestamp from the  current  completion
146              and convert it from HCA clock units to wall clock nanoseconds.
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148              uint16_t  ibv_wc_read_cvlan(struct ibv_cq_ex *cq); Get the CVLAN
149              field from the current completion.
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151              uint32_t ibv_wc_read_flow_tag(struct ibv_cq_ex  *cq);  Get  flow
152              tag from the current completion.
153
154              void    ibv_wc_read_tm_info(struct    ibv_cq_ex    *cq,   struct
155              ibv_wc_tm_info *tm_info);  Get tag matching info from  the  cur‐
156              rent completion.
157              struct ibv_wc_tm_info {
158                      uint64_t tag;  /* tag from TMH */
159                      uint32_t priv; /* opaque user data from TMH */
160              };
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RETURN VALUE

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

168       ibv_create_cq_ex() may create a CQ with size greater than or  equal  to
169       the  requested size. Check the cqe attribute in the returned CQ for the
170       actual size.
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172       CQ should be destroyed with ibv_destroy_cq.
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SEE ALSO

175       ibv_create_cq(3),         ibv_destroy_cq(3),          ibv_resize_cq(3),
176       ibv_req_notify_cq(3), ibv_ack_cq_events(3), ibv_create_qp(3)
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AUTHORS

179       Matan Barak <matanb@mellanox.com>
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183libibverbs                        2016-05-08               IBV_CREATE_CQ_EX(3)
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