From 7c091e5c0685c463dc58e5115781f7ac0a1448d6 Mon Sep 17 00:00:00 2001 From: Mike Marciniszyn Date: Tue, 10 Nov 2015 09:14:01 -0500 Subject: [PATCH] staging/rdma/hfi1: add ACK coalescing logic 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 Signed-off-by: Mike Marciniszyn Signed-off-by: Greg Kroah-Hartman --- 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 d37c4a7..ce03681 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 0c10012..6f4a155 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 6a49a3ca9..cdc844f 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 @@ -490,6 +490,7 @@ 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[] */ -- 2.7.4