[dpdk-dev] [PATCH v2] app/testpmd: fix txonly mode timestamp intitialization

Viacheslav Ovsiienko viacheslavo at mellanox.com
Wed Jul 29 14:29:54 CEST 2020


The testpmd application forwards data in multiple threads.
In the txonly mode the Tx timestamps must be initialized
on per thread basis to provide phase shift for the packet
burst being sent. This per thread initialization was performed
on zero value of the variable in thread local storage and
happened only once after testpmd forwarding start. Executing
"start" and "stop" commands did not cause thread local variables
zeroing and wrong timestamp values were used.

Fixes: 4940344dab1d ("app/testpmd: add Tx scheduling command")

Signed-off-by: Viacheslav Ovsiienko <viacheslavo at mellanox.com>

---
v1->v2: On mailing list comments addressing:
    - removed unnecessary volatile qualifier
    - comment added about the barrier
---
 app/test-pmd/txonly.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/app/test-pmd/txonly.c b/app/test-pmd/txonly.c
index 97f4a45..fe28bdb0 100644
--- a/app/test-pmd/txonly.c
+++ b/app/test-pmd/txonly.c
@@ -55,9 +55,12 @@
 static struct rte_udp_hdr pkt_udp_hdr; /**< UDP header of tx packets. */
 RTE_DEFINE_PER_LCORE(uint64_t, timestamp_qskew);
 					/**< Timestamp offset per queue */
+RTE_DEFINE_PER_LCORE(uint32_t, timestamp_idone); /**< Timestamp init done. */
+
 static uint64_t timestamp_mask; /**< Timestamp dynamic flag mask */
 static int32_t timestamp_off; /**< Timestamp dynamic field offset */
 static bool timestamp_enable; /**< Timestamp enable */
+static uint32_t timestamp_init_req; /**< Timestamp initialization request. */
 static uint64_t timestamp_initial[RTE_MAX_ETHPORTS];
 
 static void
@@ -229,7 +232,8 @@
 			rte_be64_t ts;
 		} timestamp_mark;
 
-		if (unlikely(!skew)) {
+		if (unlikely(timestamp_init_req !=
+			RTE_PER_LCORE(timestamp_idone))) {
 			struct rte_eth_dev *dev = &rte_eth_devices[fs->tx_port];
 			unsigned int txqs_n = dev->data->nb_tx_queues;
 			uint64_t phase = tx_pkt_times_inter * fs->tx_queue /
@@ -241,6 +245,7 @@
 			skew = timestamp_initial[fs->tx_port] +
 			       tx_pkt_times_inter + phase;
 			RTE_PER_LCORE(timestamp_qskew) = skew;
+			RTE_PER_LCORE(timestamp_idone) = timestamp_init_req;
 		}
 		timestamp_mark.pkt_idx = rte_cpu_to_be_16(idx);
 		timestamp_mark.queue_idx = rte_cpu_to_be_16(fs->tx_queue);
@@ -426,6 +431,10 @@
 			   timestamp_mask &&
 			   timestamp_off >= 0 &&
 			   !rte_eth_read_clock(pi, &timestamp_initial[pi]);
+	if (timestamp_enable)
+		timestamp_init_req++;
+	/* Make sure all settings are visible on forwarding cores.*/
+	rte_wmb();
 }
 
 struct fwd_engine tx_only_engine = {
-- 
1.8.3.1



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