From e998f245c4b2d36ae2c35446e54ccbf1fb29d9de Mon Sep 17 00:00:00 2001 From: Steve Wise Date: Wed, 27 Jan 2010 17:03:34 +0000 Subject: 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 Signed-off-by: Roland Dreier --- drivers/infiniband/hw/cxgb3/cxio_wr.h | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-) (limited to 'drivers/infiniband/hw/cxgb3/cxio_wr.h') diff --git a/drivers/infiniband/hw/cxgb3/cxio_wr.h b/drivers/infiniband/hw/cxgb3/cxio_wr.h index a197a5b7ac7..15073b2da1c 100644 --- a/drivers/infiniband/hw/cxgb3/cxio_wr.h +++ b/drivers/infiniband/hw/cxgb3/cxio_wr.h @@ -730,7 +730,22 @@ struct t3_cq { static inline void cxio_set_wq_in_error(struct t3_wq *wq) { - wq->queue->wq_in_err.err = 1; + wq->queue->wq_in_err.err |= 1; +} + +static inline void cxio_disable_wq_db(struct t3_wq *wq) +{ + wq->queue->wq_in_err.err |= 2; +} + +static inline void cxio_enable_wq_db(struct t3_wq *wq) +{ + wq->queue->wq_in_err.err &= ~2; +} + +static inline int cxio_wq_db_enabled(struct t3_wq *wq) +{ + return !(wq->queue->wq_in_err.err & 2); } static inline struct t3_cqe *cxio_next_hw_cqe(struct t3_cq *cq) -- cgit v1.2.3-70-g09d2