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Commit 7c091e5c authored by Mike Marciniszyn's avatar Mike Marciniszyn Committed by Greg Kroah-Hartman
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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: default avatarDennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: default avatarMike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 2fd36865

drivers/staging/rdma/hfi1/qp.c

+1 −0
Original line number Diff line number Diff line
@@ -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;

drivers/staging/rdma/hfi1/rc.c

+27 −2
Original line number Diff line number Diff line
@@ -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 @@ void hfi1_rc_rcv(struct hfi1_packet *packet) 
	qp->r_ack_psn = psn;

	qp->r_nak_state = 0;

	/* Send an ACK if requested or required. */

	if (psn & (1 << 31))

	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:

drivers/staging/rdma/hfi1/verbs.h

+4 −3
Original line number Diff line number Diff line
@@ -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[] */