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authorSteve Wise <swise@opengridcomputing.com>2010-01-27 17:03:34 +0000
committerRoland Dreier <rolandd@cisco.com>2010-02-24 10:40:28 -0800
commite998f245c4b2d36ae2c35446e54ccbf1fb29d9de (patch)
tree9a0232f2d99d37f8d47ca1f7b4dbe5e9bcde5642 /drivers/infiniband/hw/cxgb3/iwch_qp.c
parent2542322485be45853cc72d542d8ed84fae82c981 (diff)
RDMA/cxgb3: Doorbell overflow avoidance and recovery
T3 hardware doorbell FIFO overflows can cause application stalls due to lost doorbell ring events. This has been seen when running large NP IMB alltoall MPI jobs. The T3 hardware supports an xon/xoff-type flow control mechanism to help avoid overflowing the HW doorbell FIFO. This patch uses these interrupts to disable RDMA QP doorbell rings when we near an overflow condition, and then turn them back on (and ring all the active QP doorbells) when when the doorbell FIFO empties out. In addition if an doorbell ring is dropped by the hardware, the code will now recover. Design: cxgb3: - enable these DB interrupts - in the interrupt handler, schedule work tasks to call the ULPs event handlers with the new events. - ring all the qset txqs when an overflow is detected. iw_cxgb3: - disable db ringing on all active qps when we get the DB_FULL event - enable db ringing on all active qps and ring all active dbs when we get the DB_EMPTY event - On DB_DROP event: - disable db rings in the event handler - delay-schedule a work task which rings and enables the dbs on all active qps. - in post_send and post_recv logic, don't ring the db if it's disabled. Signed-off-by: Steve Wise <swise@opengridcomputing.com> Signed-off-by: Roland Dreier <rolandd@cisco.com>
Diffstat (limited to 'drivers/infiniband/hw/cxgb3/iwch_qp.c')
-rw-r--r--drivers/infiniband/hw/cxgb3/iwch_qp.c9
1 files changed, 6 insertions, 3 deletions
diff --git a/drivers/infiniband/hw/cxgb3/iwch_qp.c b/drivers/infiniband/hw/cxgb3/iwch_qp.c
index 3eb8cecf81d7..b4d893de3650 100644
--- a/drivers/infiniband/hw/cxgb3/iwch_qp.c
+++ b/drivers/infiniband/hw/cxgb3/iwch_qp.c
@@ -452,7 +452,8 @@ int iwch_post_send(struct ib_qp *ibqp, struct ib_send_wr *wr,
++(qhp->wq.sq_wptr);
}
spin_unlock_irqrestore(&qhp->lock, flag);
- ring_doorbell(qhp->wq.doorbell, qhp->wq.qpid);
+ if (cxio_wq_db_enabled(&qhp->wq))
+ ring_doorbell(qhp->wq.doorbell, qhp->wq.qpid);
out:
if (err)
@@ -514,7 +515,8 @@ int iwch_post_receive(struct ib_qp *ibqp, struct ib_recv_wr *wr,
num_wrs--;
}
spin_unlock_irqrestore(&qhp->lock, flag);
- ring_doorbell(qhp->wq.doorbell, qhp->wq.qpid);
+ if (cxio_wq_db_enabled(&qhp->wq))
+ ring_doorbell(qhp->wq.doorbell, qhp->wq.qpid);
out:
if (err)
@@ -597,7 +599,8 @@ int iwch_bind_mw(struct ib_qp *qp,
++(qhp->wq.sq_wptr);
spin_unlock_irqrestore(&qhp->lock, flag);
- ring_doorbell(qhp->wq.doorbell, qhp->wq.qpid);
+ if (cxio_wq_db_enabled(&qhp->wq))
+ ring_doorbell(qhp->wq.doorbell, qhp->wq.qpid);
return err;
}