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authorBryan O'Sullivan <bos@pathscale.com>2006-09-28 08:59:57 -0700
committerRoland Dreier <rolandd@cisco.com>2006-09-28 11:16:21 -0700
commit6022943eb4cb3cb9e43f27f1faeaba38e162d966 (patch)
tree0c495a94448610e20a4872416b85c8ffdb0f2adf /drivers/infiniband/hw/ipath/ipath_rc.c
parentfd6a79a786b84510d00ee6aa6449a468e6d75dee (diff)
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>
Diffstat (limited to 'drivers/infiniband/hw/ipath/ipath_rc.c')
-rw-r--r--drivers/infiniband/hw/ipath/ipath_rc.c47
1 files changed, 29 insertions, 18 deletions
diff --git a/drivers/infiniband/hw/ipath/ipath_rc.c b/drivers/infiniband/hw/ipath/ipath_rc.c
index a08654042c0..52caa2edf5a 100644
--- a/drivers/infiniband/hw/ipath/ipath_rc.c
+++ b/drivers/infiniband/hw/ipath/ipath_rc.c
@@ -201,6 +201,18 @@ int ipath_make_rc_req(struct ipath_qp *qp,
qp->s_rnr_timeout)
goto done;
+ /* Limit the number of packets sent without an ACK. */
+ if (ipath_cmp24(qp->s_psn, qp->s_last_psn + IPATH_PSN_CREDIT) > 0) {
+ qp->s_wait_credit = 1;
+ dev->n_rc_stalls++;
+ spin_lock(&dev->pending_lock);
+ if (list_empty(&qp->timerwait))
+ list_add_tail(&qp->timerwait,
+ &dev->pending[dev->pending_index]);
+ spin_unlock(&dev->pending_lock);
+ goto done;
+ }
+
/* header size in 32-bit words LRH+BTH = (8+12)/4. */
hwords = 5;
bth0 = 0;
@@ -221,7 +233,7 @@ int ipath_make_rc_req(struct ipath_qp *qp,
/* Check if send work queue is empty. */
if (qp->s_tail == qp->s_head)
goto done;
- qp->s_psn = wqe->psn = qp->s_next_psn;
+ wqe->psn = qp->s_next_psn;
newreq = 1;
}
/*
@@ -393,12 +405,6 @@ int ipath_make_rc_req(struct ipath_qp *qp,
ss = &qp->s_sge;
len = qp->s_len;
if (len > pmtu) {
- /*
- * Request an ACK every 1/2 MB to avoid retransmit
- * timeouts.
- */
- if (((wqe->length - len) % (512 * 1024)) == 0)
- bth2 |= 1 << 31;
len = pmtu;
break;
}
@@ -435,12 +441,6 @@ int ipath_make_rc_req(struct ipath_qp *qp,
ss = &qp->s_sge;
len = qp->s_len;
if (len > pmtu) {
- /*
- * Request an ACK every 1/2 MB to avoid retransmit
- * timeouts.
- */
- if (((wqe->length - len) % (512 * 1024)) == 0)
- bth2 |= 1 << 31;
len = pmtu;
break;
}
@@ -498,6 +498,8 @@ int ipath_make_rc_req(struct ipath_qp *qp,
*/
goto done;
}
+ if (ipath_cmp24(qp->s_psn, qp->s_last_psn + IPATH_PSN_CREDIT - 1) >= 0)
+ bth2 |= 1 << 31; /* Request ACK. */
qp->s_len -= len;
qp->s_hdrwords = hwords;
qp->s_cur_sge = ss;
@@ -737,6 +739,15 @@ bail:
return;
}
+static inline void update_last_psn(struct ipath_qp *qp, u32 psn)
+{
+ if (qp->s_wait_credit) {
+ qp->s_wait_credit = 0;
+ tasklet_hi_schedule(&qp->s_task);
+ }
+ qp->s_last_psn = psn;
+}
+
/**
* do_rc_ack - process an incoming RC ACK
* @qp: the QP the ACK came in on
@@ -805,7 +816,7 @@ static int do_rc_ack(struct ipath_qp *qp, u32 aeth, u32 psn, int opcode)
* The last valid PSN seen is the previous
* request's.
*/
- qp->s_last_psn = wqe->psn - 1;
+ update_last_psn(qp, wqe->psn - 1);
/* Retry this request. */
ipath_restart_rc(qp, wqe->psn, &wc);
/*
@@ -864,7 +875,7 @@ static int do_rc_ack(struct ipath_qp *qp, u32 aeth, u32 psn, int opcode)
ipath_get_credit(qp, aeth);
qp->s_rnr_retry = qp->s_rnr_retry_cnt;
qp->s_retry = qp->s_retry_cnt;
- qp->s_last_psn = psn;
+ update_last_psn(qp, psn);
ret = 1;
goto bail;
@@ -883,7 +894,7 @@ static int do_rc_ack(struct ipath_qp *qp, u32 aeth, u32 psn, int opcode)
goto bail;
/* The last valid PSN is the previous PSN. */
- qp->s_last_psn = psn - 1;
+ update_last_psn(qp, psn - 1);
dev->n_rc_resends += (int)qp->s_psn - (int)psn;
@@ -898,7 +909,7 @@ static int do_rc_ack(struct ipath_qp *qp, u32 aeth, u32 psn, int opcode)
case 3: /* NAK */
/* The last valid PSN seen is the previous request's. */
if (qp->s_last != qp->s_tail)
- qp->s_last_psn = wqe->psn - 1;
+ update_last_psn(qp, wqe->psn - 1);
switch ((aeth >> IPATH_AETH_CREDIT_SHIFT) &
IPATH_AETH_CREDIT_MASK) {
case 0: /* PSN sequence error */
@@ -1071,7 +1082,7 @@ static inline void ipath_rc_rcv_resp(struct ipath_ibdev *dev,
* since we don't want s_sge modified.
*/
qp->s_len -= pmtu;
- qp->s_last_psn = psn;
+ update_last_psn(qp, psn);
spin_unlock_irqrestore(&qp->s_lock, flags);
ipath_copy_sge(&qp->s_sge, data, pmtu);
goto bail;