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authorRalph Campbell <ralph.campbell@qlogic.com>2008-04-16 21:09:27 -0700
committerRoland Dreier <rolandd@cisco.com>2008-04-16 21:09:27 -0700
commitd98b1937768c9f4e4420bd25406e5f0304d224bb (patch)
tree306b10016a5ada414efa187ba071808a304be8bd /drivers/infiniband
parentc4b4d16e090e1b68d1d4d20a28757070982b9725 (diff)
IB/ipath: Use PIO buffer for RC ACKs
This reduces the latency for RC ACKs when a PIO buffer is available. Signed-off-by: Ralph Campbell <ralph.campbell@qlogic.com> Signed-off-by: Roland Dreier <rolandd@cisco.com>
Diffstat (limited to 'drivers/infiniband')
-rw-r--r--drivers/infiniband/hw/ipath/ipath_rc.c57
1 files changed, 39 insertions, 18 deletions
diff --git a/drivers/infiniband/hw/ipath/ipath_rc.c b/drivers/infiniband/hw/ipath/ipath_rc.c
index 40f3e37d7ad..f765d48464a 100644
--- a/drivers/infiniband/hw/ipath/ipath_rc.c
+++ b/drivers/infiniband/hw/ipath/ipath_rc.c
@@ -31,6 +31,8 @@
* SOFTWARE.
*/
+#include <linux/io.h>
+
#include "ipath_verbs.h"
#include "ipath_kernel.h"
@@ -585,19 +587,39 @@ bail:
static void send_rc_ack(struct ipath_qp *qp)
{
struct ipath_ibdev *dev = to_idev(qp->ibqp.device);
+ struct ipath_devdata *dd;
u16 lrh0;
u32 bth0;
u32 hwords;
+ u32 __iomem *piobuf;
struct ipath_ib_header hdr;
struct ipath_other_headers *ohdr;
unsigned long flags;
+ spin_lock_irqsave(&qp->s_lock, flags);
+
/* Don't send ACK or NAK if a RDMA read or atomic is pending. */
if (qp->r_head_ack_queue != qp->s_tail_ack_queue ||
(qp->s_flags & IPATH_S_ACK_PENDING) ||
qp->s_ack_state != OP(ACKNOWLEDGE))
goto queue_ack;
+ spin_unlock_irqrestore(&qp->s_lock, flags);
+
+ dd = dev->dd;
+ piobuf = ipath_getpiobuf(dd, 0, NULL);
+ if (!piobuf) {
+ /*
+ * We are out of PIO buffers at the moment.
+ * Pass responsibility for sending the ACK to the
+ * send tasklet so that when a PIO buffer becomes
+ * available, the ACK is sent ahead of other outgoing
+ * packets.
+ */
+ spin_lock_irqsave(&qp->s_lock, flags);
+ goto queue_ack;
+ }
+
/* Construct the header. */
ohdr = &hdr.u.oth;
lrh0 = IPATH_LRH_BTH;
@@ -611,7 +633,7 @@ static void send_rc_ack(struct ipath_qp *qp)
lrh0 = IPATH_LRH_GRH;
}
/* read pkey_index w/o lock (its atomic) */
- bth0 = ipath_get_pkey(dev->dd, qp->s_pkey_index) |
+ bth0 = ipath_get_pkey(dd, qp->s_pkey_index) |
(OP(ACKNOWLEDGE) << 24) | (1 << 22);
if (qp->r_nak_state)
ohdr->u.aeth = cpu_to_be32((qp->r_msn & IPATH_MSN_MASK) |
@@ -623,30 +645,29 @@ static void send_rc_ack(struct ipath_qp *qp)
hdr.lrh[0] = cpu_to_be16(lrh0);
hdr.lrh[1] = cpu_to_be16(qp->remote_ah_attr.dlid);
hdr.lrh[2] = cpu_to_be16(hwords + SIZE_OF_CRC);
- hdr.lrh[3] = cpu_to_be16(dev->dd->ipath_lid);
+ hdr.lrh[3] = cpu_to_be16(dd->ipath_lid);
ohdr->bth[0] = cpu_to_be32(bth0);
ohdr->bth[1] = cpu_to_be32(qp->remote_qpn);
ohdr->bth[2] = cpu_to_be32(qp->r_ack_psn & IPATH_PSN_MASK);
- /*
- * If we can send the ACK, clear the ACK state.
- */
- if (ipath_verbs_send(qp, &hdr, hwords, NULL, 0) == 0) {
- dev->n_unicast_xmit++;
- goto done;
- }
+ writeq(hwords + 1, piobuf);
- /*
- * We are out of PIO buffers at the moment.
- * Pass responsibility for sending the ACK to the
- * send tasklet so that when a PIO buffer becomes
- * available, the ACK is sent ahead of other outgoing
- * packets.
- */
- dev->n_rc_qacks++;
+ if (dd->ipath_flags & IPATH_PIO_FLUSH_WC) {
+ u32 *hdrp = (u32 *) &hdr;
+
+ ipath_flush_wc();
+ __iowrite32_copy(piobuf + 2, hdrp, hwords - 1);
+ ipath_flush_wc();
+ __raw_writel(hdrp[hwords - 1], piobuf + hwords + 1);
+ } else
+ __iowrite32_copy(piobuf + 2, (u32 *) &hdr, hwords);
+
+ ipath_flush_wc();
+
+ dev->n_unicast_xmit++;
+ goto done;
queue_ack:
- spin_lock_irqsave(&qp->s_lock, flags);
dev->n_rc_qacks++;
qp->s_flags |= IPATH_S_ACK_PENDING;
qp->s_nak_state = qp->r_nak_state;