IB/qib: Precompute timeout jiffies to optimize latency
A new field is added to qib_qp called timeout_jiffies. It is
initialized upon create and modify.
The field is now used instead of a computation based on qp->timeout.
Signed-off-by: Mike Marciniszyn <mike.marciniszyn@qlogic.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
diff --git a/drivers/infiniband/hw/qib/qib_qp.c b/drivers/infiniband/hw/qib/qib_qp.c
index 500981b..7e7e16f 100644
--- a/drivers/infiniband/hw/qib/qib_qp.c
+++ b/drivers/infiniband/hw/qib/qib_qp.c
@@ -801,8 +801,12 @@
if (attr_mask & IB_QP_MIN_RNR_TIMER)
qp->r_min_rnr_timer = attr->min_rnr_timer;
- if (attr_mask & IB_QP_TIMEOUT)
+ if (attr_mask & IB_QP_TIMEOUT) {
qp->timeout = attr->timeout;
+ qp->timeout_jiffies =
+ usecs_to_jiffies((4096UL * (1UL << qp->timeout)) /
+ 1000UL);
+ }
if (attr_mask & IB_QP_QKEY)
qp->qkey = attr->qkey;
@@ -1034,6 +1038,9 @@
goto bail_swq;
}
RCU_INIT_POINTER(qp->next, NULL);
+ qp->timeout_jiffies =
+ usecs_to_jiffies((4096UL * (1UL << qp->timeout)) /
+ 1000UL);
if (init_attr->srq)
sz = 0;
else {