From: Mike Marciniszyn <mike.marciniszyn@xxxxxxxxx>
The adaptive PIO implementation only considers the current packet size
when deciding between SDMA and pio for a packet.
This causes credit return forces if small and large packets
are interleaved.
Add a running average to avoid costly credit forces so that a large
sequence of small packets is required to go below the threshold
that chooses pio.
Reviewed-by: Michael J. Ruhl <michael.j.ruhl@xxxxxxxxx>
Signed-off-by: Mike Marciniszyn <mike.marciniszyn@xxxxxxxxx>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@xxxxxxxxx>
---
drivers/infiniband/hw/hfi1/qp.c | 2 ++
drivers/infiniband/hw/hfi1/verbs.c | 7 ++++---
drivers/infiniband/hw/hfi1/verbs.h | 1 +
3 files changed, 7 insertions(+), 3 deletions(-)
diff --git a/drivers/infiniband/hw/hfi1/qp.c b/drivers/infiniband/hw/hfi1/qp.c
index 9b643c2..1390172 100644
--- a/drivers/infiniband/hw/hfi1/qp.c
+++ b/drivers/infiniband/hw/hfi1/qp.c
@@ -742,6 +742,8 @@ void qp_iter_print(struct seq_file *s, struct rvt_qp_iter *iter)
iowait_wakeup,
iowait_sdma_drained,
hfi1_init_priority);
+ /* Init to a value to start the running average correctly */
+ priv->s_running_pkt_size = piothreshold / 2;
return priv;
}
diff --git a/drivers/infiniband/hw/hfi1/verbs.c b/drivers/infiniband/hw/hfi1/verbs.c
index 55a56b3..b73ab7c 100644
--- a/drivers/infiniband/hw/hfi1/verbs.c
+++ b/drivers/infiniband/hw/hfi1/verbs.c
@@ -1223,15 +1223,16 @@ static inline send_routine get_send_routine(struct rvt_qp *qp,
case IB_QPT_UD:
break;
case IB_QPT_UC:
- case IB_QPT_RC: {
+ case IB_QPT_RC:
+ priv->s_running_pkt_size =
+ (tx->s_cur_size + priv->s_running_pkt_size) / 2;
if (piothreshold &&
- tx->s_cur_size <= min(piothreshold, qp->pmtu) &&
+ priv->s_running_pkt_size <= min(piothreshold, qp->pmtu) &&
(BIT(ps->opcode & OPMASK) & pio_opmask[ps->opcode >> 5]) &&
iowait_sdma_pending(&priv->s_iowait) == 0 &&
!sdma_txreq_built(&tx->txreq))
return dd->process_pio_send;
break;
- }
default:
break;
}
diff --git a/drivers/infiniband/hw/hfi1/verbs.h b/drivers/infiniband/hw/hfi1/verbs.h
index 62ace0b..7ecb8ed 100644
--- a/drivers/infiniband/hw/hfi1/verbs.h
+++ b/drivers/infiniband/hw/hfi1/verbs.h
@@ -170,6 +170,7 @@ struct hfi1_qp_priv {
struct tid_flow_state flow_state;
struct tid_rdma_qp_params tid_rdma;
struct rvt_qp *owner;
+ u16 s_running_pkt_size;
u8 hdr_type; /* 9B or 16B */
struct rvt_sge_state tid_ss; /* SGE state pointer for 2nd leg */
atomic_t n_requests; /* # of TID RDMA requests in the */
