redonkable/alistair23-linux
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staging/rdma/hfi1: add ACK coalescing logic

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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@intel.com>
Signed-off-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Mike Marciniszyn 2015-11-10 09:14:01 -05:00 committed by Greg Kroah-Hartman
parent 2fd36865b5
commit 7c091e5c06
3 changed files with 32 additions and 5 deletions
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1
drivers/staging/rdma/hfi1/qp.c
View file

@ -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;

29
drivers/staging/rdma/hfi1/rc.c
View file

@ -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:

7
drivers/staging/rdma/hfi1/verbs.h
View file

@ -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[] */