IB/ipath: Limit # of packets sent without an ACK received

The sender requests an ACK every 1/2 MB to avoid retransmit timeouts that
were causing MVAPICH mod_bw to fail after a predictable number of sends.

Signed-off-by: Bryan O'Sullivan <bryan.osullivan@qlogic.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/drivers/infiniband/hw/ipath/ipath_verbs.h b/drivers/infiniband/hw/ipath/ipath_verbs.h
index 09bbb3f9a21..3fffaa02e66 100644
--- a/drivers/infiniband/hw/ipath/ipath_verbs.h
+++ b/drivers/infiniband/hw/ipath/ipath_verbs.h
@@ -370,6 +370,7 @@ struct ipath_qp {
         u8 s_rnr_retry_cnt;
         u8 s_retry;             /* requester retry counter */
         u8 s_rnr_retry;         /* requester RNR retry counter */
+        u8 s_wait_credit;       /* limit number of unacked packets sent */
         u8 s_pkey_index;        /* PKEY index to use */
         u8 timeout;             /* Timeout for this QP */
         enum ib_mtu path_mtu;
@@ -393,6 +394,8 @@ struct ipath_qp {
 #define IPATH_S_BUSY            0
 #define IPATH_S_SIGNAL_REQ_WR   1
 
+#define IPATH_PSN_CREDIT        2048
+
 /*
  * Since struct ipath_swqe is not a fixed size, we can't simply index into
  * struct ipath_qp.s_wq.  This function does the array index computation.
@@ -521,6 +524,7 @@ struct ipath_ibdev {
         u32 n_rnr_naks;
         u32 n_other_naks;
         u32 n_timeouts;
+        u32 n_rc_stalls;
         u32 n_pkt_drops;
         u32 n_vl15_dropped;
         u32 n_wqe_errs;