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From: Rahul Lakkireddy <rahul.lakkireddy@chelsio.com>
To: dev@dpdk.org
Date: Fri, 20 Nov 2015 18:43:38 +0530
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Cc: Felix Marti <felix@chelsio.com>, Kumar Sanghvi <kumaras@chelsio.com>,
Nirranjan Kirubaharan <nirranjan@chelsio.com>
Subject: [dpdk-dev] [PATCH 2/2] cxgbe: fix unnecessary spinning for a lock
with trylock instead
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CXGBE PMD depends on an alarm to periodically transmit any pending
coalesced packets and hence spins for a lock for each tx queue in the
alarm callback.
A better solution is to try to get a lock whenever possible, instead
of spinning for it.
Signed-off-by: Rahul Lakkireddy <rahul.lakkireddy@chelsio.com>
Signed-off-by: Kumar Sanghvi <kumaras@chelsio.com>
---
drivers/net/cxgbe/base/adapter.h | 9 +++++++++
drivers/net/cxgbe/sge.c | 21 ++++++++++++---------
2 files changed, 21 insertions(+), 9 deletions(-)
diff --git a/drivers/net/cxgbe/base/adapter.h b/drivers/net/cxgbe/base/adapter.h
index a1e8ef7..a5225c0 100644
--- a/drivers/net/cxgbe/base/adapter.h
+++ b/drivers/net/cxgbe/base/adapter.h
@@ -473,6 +473,15 @@ static inline void t4_os_unlock(rte_spinlock_t *lock)
}
/**
+ * t4_os_trylock - try to get a lock
+ * @lock: the spinlock
+ */
+static inline int t4_os_trylock(rte_spinlock_t *lock)
+{
+ return rte_spinlock_trylock(lock);
+}
+
+/**
* t4_os_init_list_head - initialize
* @head: head of list to initialize [to empty]
*/
diff --git a/drivers/net/cxgbe/sge.c b/drivers/net/cxgbe/sge.c
index aa0c2e5..51449e0 100644
--- a/drivers/net/cxgbe/sge.c
+++ b/drivers/net/cxgbe/sge.c
@@ -808,20 +808,23 @@ static void tx_timer_cb(void *data)
struct adapter *adap = (struct adapter *)data;
struct sge_eth_txq *txq = &adap->sge.ethtxq[0];
int i;
+ unsigned int coal_idx;
/* monitor any pending tx */
for (i = 0; i < adap->sge.max_ethqsets; i++, txq++) {
- t4_os_lock(&txq->txq_lock);
- if (txq->q.coalesce.idx) {
- if (txq->q.coalesce.idx == txq->q.last_coal_idx &&
- txq->q.pidx == txq->q.last_pidx) {
- ship_tx_pkt_coalesce_wr(adap, txq);
- } else {
- txq->q.last_coal_idx = txq->q.coalesce.idx;
- txq->q.last_pidx = txq->q.pidx;
+ if (t4_os_trylock(&txq->txq_lock)) {
+ coal_idx = txq->q.coalesce.idx;
+ if (coal_idx) {
+ if (coal_idx == txq->q.last_coal_idx &&
+ txq->q.pidx == txq->q.last_pidx) {
+ ship_tx_pkt_coalesce_wr(adap, txq);
+ } else {
+ txq->q.last_coal_idx = coal_idx;
+ txq->q.last_pidx = txq->q.pidx;
+ }
}
+ t4_os_unlock(&txq->txq_lock);
}
- t4_os_unlock(&txq->txq_lock);
}
rte_eal_alarm_set(50, tx_timer_cb, (void *)adap);
}
--
2.5.3