Steve Wise wrote: > On 11/29/2010 11:34 AM, Robert D. Russell wrote: > See section 8.2.1 of the iWARP Verbs draft at: > http://tools.ietf.org/html/draft-hilland-rddp-verbs-00#section-8.2.1. > The last big paragraph in 8.2.1 spells it all out. > There should be a similar requirement in the IBTA IB Verbs specification...
Yes, I think the below patch to the man page can help people understand how to work with the thing >>> You must signal one WR for every SQ-depth worth of WRs posted. IE: >>> If your SQ depth is 16, you must signal at least one out of every 16 >>> This ensures proper flow control for HW resources. clarify selective signaling usage Signed-off-by: Or Gerlitz <[email protected]> --- man/ibv_post_send.3 | 6 ++++++ 1 file changed, 6 insertions(+) Index: libibverbs/man/ibv_post_send.3 =================================================================== --- libibverbs.orig/man/ibv_post_send.3 +++ libibverbs/man/ibv_post_send.3 @@ -112,6 +112,12 @@ request is fully executed and a work com from the corresponding completion queue (CQ). However, if the IBV_SEND_INLINE flag was set, the buffer can be reused immediately after the call returns. +.PP +Applications which use selective signaling should make sure to post +a signaled WR (i.e one for which the IBV_SEND_SIGNALED flag is set) from +time to time - depending on the requirements of the underlying rdma device. +Typically the number of consecutive unsignaled WRs should not exceed the +size of the send queue specified when the QP was created. .SH "SEE ALSO" .BR ibv_create_qp (3), .BR ibv_create_ah (3), -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
