| .\" -*- nroff -*- |
| .\" |
| .TH IBV_MODIFY_SRQ 3 2006-10-31 libibverbs "Libibverbs Programmer's Manual" |
| .SH "NAME" |
| ibv_modify_srq \- modify attributes of a shared receive queue (SRQ) |
| .SH "SYNOPSIS" |
| .nf |
| .B #include <infiniband/verbs.h> |
| .sp |
| .BI "int ibv_modify_srq(struct ibv_srq " "*srq" , |
| .BI " struct ibv_srq_attr " "*srq_attr" , |
| .BI " int " "srq_attr_mask" ); |
| .fi |
| .SH "DESCRIPTION" |
| .B ibv_modify_srq() |
| modifies the attributes of SRQ |
| .I srq |
| with the attributes in |
| .I srq_attr |
| according to the mask |
| .I srq_attr_mask\fR. |
| The argument \fIsrq_attr\fR is an ibv_srq_attr struct, as defined in <infiniband/verbs.h>. |
| .PP |
| .nf |
| struct ibv_srq_attr { |
| .in +8 |
| uint32_t max_wr; /* maximum number of outstanding work requests (WRs) in the SRQ */ |
| uint32_t max_sge; /* number of scatter elements per WR (irrelevant for ibv_modify_srq) */ |
| uint32_t srq_limit; /* the limit value of the SRQ */ |
| .in -8 |
| }; |
| .fi |
| .PP |
| The argument |
| .I srq_attr_mask |
| specifies the SRQ attributes to be modified. |
| The argument is either 0 or the bitwise OR of one or more of the following flags: |
| .PP |
| .TP |
| .B IBV_SRQ_MAX_WR \fR Resize the SRQ |
| .TP |
| .B IBV_SRQ_LIMIT \fR Set the SRQ limit |
| .SH "RETURN VALUE" |
| .B ibv_modify_srq() |
| returns 0 on success, or the value of errno on failure (which indicates the failure reason). |
| .SH "NOTES" |
| If any of the modify attributes is invalid, none of the attributes will be modified. |
| .PP |
| Not all devices support resizing SRQs. To check if a device supports it, check if the |
| .B IBV_DEVICE_SRQ_RESIZE |
| bit is set in the device capabilities flags. |
| .PP |
| Modifying the srq_limit arms the SRQ to produce an |
| .B IBV_EVENT_SRQ_LIMIT_REACHED |
| "low watermark" asynchronous event once the number of WRs in the SRQ drops below srq_limit. |
| .SH "SEE ALSO" |
| .BR ibv_query_device (3), |
| .BR ibv_create_srq (3), |
| .BR ibv_destroy_srq (3), |
| .BR ibv_query_srq (3) |
| .SH "AUTHORS" |
| .TP |
| Dotan Barak <dotanba@gmail.com> |