Implement ACK coalesing logic using a 8 bit counter.
The algorithm is send pio ack when:
- fecn present
- this is the first packet in an interrupt session
- counter is >= HFI1_PSN_CREDIT
Otherwise the ack is defered.
Reviewed-by: Dennis Dalessandro <dennis.dalessandro@xxxxxxxxx>
Signed-off-by: Mike Marciniszyn <mike.marciniszyn@xxxxxxxxx>
---
drivers/staging/rdma/hfi1/qp.c | 1 +
drivers/staging/rdma/hfi1/rc.c | 29 +++++++++++++++++++++++++++--
drivers/staging/rdma/hfi1/verbs.h | 7 ++++---
3 files changed, 32 insertions(+), 5 deletions(-)
diff --git a/drivers/staging/rdma/hfi1/qp.c b/drivers/staging/rdma/hfi1/qp.c
index df1fa56..8f867ba 100644
--- a/drivers/staging/rdma/hfi1/qp.c
+++ b/drivers/staging/rdma/hfi1/qp.c
@@ -378,6 +378,7 @@ static void reset_qp(struct hfi1_qp *qp, enum ib_qp_type type)
}
qp->s_ack_state = IB_OPCODE_RC_ACKNOWLEDGE;
qp->r_nak_state = 0;
+ qp->r_adefered = 0;
qp->r_aflags = 0;
qp->r_flags = 0;
qp->s_head = 0;
diff --git a/drivers/staging/rdma/hfi1/rc.c b/drivers/staging/rdma/hfi1/rc.c
index 6fe0104..0193497 100644
--- a/drivers/staging/rdma/hfi1/rc.c
+++ b/drivers/staging/rdma/hfi1/rc.c
@@ -1618,6 +1618,17 @@ static inline void rc_defered_ack(struct hfi1_ctxtdata *rcd,
}
}
+static inline void rc_cancel_ack(struct hfi1_qp *qp)
+{
+ qp->r_adefered = 0;
+ if (list_empty(&qp->rspwait))
+ return;
+ list_del_init(&qp->rspwait);
+ qp->r_flags &= ~HFI1_R_RSP_DEFERED_ACK;
+ if (atomic_dec_and_test(&qp->refcount))
+ wake_up(&qp->wait);
+}
+
/**
* rc_rcv_error - process an incoming duplicate or error RC packet
* @ohdr: the other headers for this packet
@@ -2335,8 +2346,22 @@ send_last:
qp->r_ack_psn = psn;
qp->r_nak_state = 0;
/* Send an ACK if requested or required. */
- if (psn & (1 << 31))
- goto send_ack;
+ if (psn & IB_BTH_REQ_ACK) {
+ if (packet->numpkt == 0) {
+ rc_cancel_ack(qp);
+ goto send_ack;
+ }
+ if (qp->r_adefered >= HFI1_PSN_CREDIT) {
+ rc_cancel_ack(qp);
+ goto send_ack;
+ }
+ if (unlikely(is_fecn)) {
+ rc_cancel_ack(qp);
+ goto send_ack;
+ }
+ qp->r_adefered++;
+ rc_defered_ack(rcd, qp);
+ }
return;
rnr_nak:
diff --git a/drivers/staging/rdma/hfi1/verbs.h b/drivers/staging/rdma/hfi1/verbs.h
index c5e6f47..6d2012b 100644
--- a/drivers/staging/rdma/hfi1/verbs.h
+++ b/drivers/staging/rdma/hfi1/verbs.h
@@ -120,9 +120,9 @@ struct hfi1_packet;
#define HFI1_VENDOR_IPG cpu_to_be16(0xFFA0)
-#define IB_BTH_REQ_ACK (1 << 31)
-#define IB_BTH_SOLICITED (1 << 23)
-#define IB_BTH_MIG_REQ (1 << 22)
+#define IB_BTH_REQ_ACK BIT(31)
+#define IB_BTH_SOLICITED BIT(23)
+#define IB_BTH_MIG_REQ BIT(22)
#define IB_GRH_VERSION 6
#define IB_GRH_VERSION_MASK 0xF
@@ -484,6 +484,7 @@ struct hfi1_qp {
u32 r_psn; /* expected rcv packet sequence number */
u32 r_msn; /* message sequence number */
+ u8 r_adefered; /* number of acks defered */
u8 r_state; /* opcode of last packet received */
u8 r_flags;
u8 r_head_ack_queue; /* index into s_ack_queue[] */
--
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