[dpdk-dev] [[PATCH v3 4/4] net/pcap: support hardware Tx timestamps

Patrick Keroulas patrick.keroulas at radio-canada.ca
Fri Jul 24 22:23:15 CEST 2020


From: Vivien Didelot <vivien.didelot at gmail.com>

When hardware timestamping is enabled on Rx path, system time should
no longer be used to calculate the timestamps when dumping packets.

Instead, use the value stored by the driver in mbuf->timestamp
and assume it is already converted to nanoseconds (otherwise the
application may edit the packet headers itself afterwards).

Signed-off-by: Vivien Didelot <vivien.didelot at gmail.com>
Signed-off-by: Patrick Keroulas <patrick.keroulas at radio-canada.ca>
---
 doc/guides/rel_notes/release_20_08.rst |  1 +
 drivers/net/pcap/rte_eth_pcap.c        | 32 +++++++++++++-----------
 lib/librte_pdump/rte_pdump.c           | 34 ++++++++++++++------------
 3 files changed, 37 insertions(+), 30 deletions(-)

diff --git a/doc/guides/rel_notes/release_20_08.rst b/doc/guides/rel_notes/release_20_08.rst
index 89822bcb8d..bda2f7567a 100644
--- a/doc/guides/rel_notes/release_20_08.rst
+++ b/doc/guides/rel_notes/release_20_08.rst
@@ -105,6 +105,7 @@ New Features
   Updated PCAP driver with new features and improvements, including:
 
   * Support software Tx nanosecond timestamps precision.
+  * Support hardware Tx timestamps.
 
 * **Updated Broadcom bnxt driver.**
 
diff --git a/drivers/net/pcap/rte_eth_pcap.c b/drivers/net/pcap/rte_eth_pcap.c
index 668cbd1fc7..45775951f7 100644
--- a/drivers/net/pcap/rte_eth_pcap.c
+++ b/drivers/net/pcap/rte_eth_pcap.c
@@ -290,19 +290,23 @@ eth_null_rx(void *queue __rte_unused,
 #define NSEC_PER_SEC	1000000000L
 
 static inline void
-calculate_timestamp(struct timeval *ts) {
-	uint64_t cycles;
-	struct timeval cur_time;
-
-	cycles = rte_get_timer_cycles() - start_cycles;
-	cur_time.tv_sec = cycles / hz;
-	cur_time.tv_usec = (cycles % hz) * NSEC_PER_SEC / hz;
-
-	ts->tv_sec = start_time.tv_sec + cur_time.tv_sec;
-	ts->tv_usec = start_time.tv_usec + cur_time.tv_usec;
-	if (ts->tv_usec >= NSEC_PER_SEC) {
-		ts->tv_usec -= NSEC_PER_SEC;
-		ts->tv_sec += 1;
+calculate_timestamp(const struct rte_mbuf *mbuf, struct timeval *ts) {
+	if (mbuf->ol_flags & PKT_RX_TIMESTAMP) {
+		ts->tv_sec = mbuf->timestamp / NSEC_PER_SEC;
+		ts->tv_usec = mbuf->timestamp % NSEC_PER_SEC;
+	} else {
+		uint64_t cycles = rte_get_timer_cycles() - start_cycles;
+		struct timeval cur_time = {
+			.tv_sec = cycles / hz,
+			.tv_usec = (cycles % hz) * NSEC_PER_SEC / hz,
+		};
+
+		ts->tv_sec = start_time.tv_sec + cur_time.tv_sec;
+		ts->tv_usec = start_time.tv_usec + cur_time.tv_usec;
+		if (ts->tv_usec >= NSEC_PER_SEC) {
+			ts->tv_usec -= NSEC_PER_SEC;
+			ts->tv_sec += 1;
+		}
 	}
 }
 
@@ -339,7 +343,7 @@ eth_pcap_tx_dumper(void *queue, struct rte_mbuf **bufs, uint16_t nb_pkts)
 			caplen = sizeof(temp_data);
 		}
 
-		calculate_timestamp(&header.ts);
+		calculate_timestamp(mbuf, &header.ts);
 		header.len = len;
 		header.caplen = caplen;
 		/* rte_pktmbuf_read() returns a pointer to the data directly
diff --git a/lib/librte_pdump/rte_pdump.c b/lib/librte_pdump/rte_pdump.c
index 8fd7e13af5..e8963e9dd8 100644
--- a/lib/librte_pdump/rte_pdump.c
+++ b/lib/librte_pdump/rte_pdump.c
@@ -71,21 +71,6 @@ static struct pdump_rxtx_cbs {
 } rx_cbs[RTE_MAX_ETHPORTS][RTE_MAX_QUEUES_PER_PORT],
 tx_cbs[RTE_MAX_ETHPORTS][RTE_MAX_QUEUES_PER_PORT];
 
-static uint64_t hz;
-static uint64_t start_time;
-static uint64_t start_cycles;
-
-static inline void
-pdump_ts_to_ns(struct rte_mbuf **pkts, uint16_t nb_pkts)
-{
-	unsigned int i;
-
-	for (i = 0; i < nb_pkts; i++) {
-		if ((pkts[i]->ol_flags & PKT_RX_TIMESTAMP) && hz)
-			pkts[i]->timestamp = start_time +
-				 (pkts[i]->timestamp - start_cycles) * NS_PER_S / hz;
-	}
-}
 
 static inline void
 pdump_copy(struct rte_mbuf **pkts, uint16_t nb_pkts, void *user_params)
@@ -118,6 +103,23 @@ pdump_copy(struct rte_mbuf **pkts, uint16_t nb_pkts, void *user_params)
 	}
 }
 
+#define NSEC_PER_SEC 1000000000L
+static uint64_t hz;
+static uint64_t start_time;
+static uint64_t start_cycles;
+
+static inline void
+pdump_ts_to_ns(struct rte_mbuf **pkts, uint16_t nb_pkts)
+{
+	unsigned int i;
+
+	for (i = 0; i < nb_pkts; i++) {
+		if ((pkts[i]->ol_flags & PKT_RX_TIMESTAMP) && hz)
+			pkts[i]->timestamp = start_time +
+				 (pkts[i]->timestamp - start_cycles) * NSEC_PER_SEC / hz;
+	}
+}
+
 static uint16_t
 pdump_rx(uint16_t port __rte_unused, uint16_t qidx __rte_unused,
 	struct rte_mbuf **pkts, uint16_t nb_pkts,
@@ -154,7 +156,7 @@ pdump_register_rx_callbacks(uint16_t end_q, uint16_t port, uint16_t queue,
 			rte_eth_read_clock(port, &start_cycles);
 			rte_eth_get_clock_freq(port, &hz);
 			gettimeofday(&now, NULL);
-			start_time = now.tv_sec * NS_PER_S + now.tv_usec * 1000;
+			start_time = now.tv_sec * NSEC_PER_SEC + now.tv_usec * 1000;
 
 			if (cbs->cb) {
 				PDUMP_LOG(ERR,
-- 
2.17.1



More information about the dev mailing list