[PATCH v4 3/6] net/nfb: update timestamp calculation to meaningful value

spinler
2026-01-21T17:02:22Z

The resulting timestamp wasn't monotonically increasing value.

Now the timestamp is value in nanoseconds (Unix epoch).

Unfortunately there's currently no safe mechanism in nfb-framework
to get ticks from hardware to implement read_clock function.

Signed-off-by: Martin Spinler <spinler@cesnet.cz>
---
doc/guides/nics/nfb.rst | 6 ++----
drivers/net/nfb/nfb_rx.h | 13 +++++++------
2 files changed, 9 insertions(+), 10 deletions(-)

diff --git a/doc/guides/nics/nfb.rst b/doc/guides/nics/nfb.rst
index 96aaf64440..a9b4049654 100644
--- a/doc/guides/nics/nfb.rst
+++ b/doc/guides/nics/nfb.rst
@@ -64,10 +64,8 @@ products). The standard `RTE_ETH_RX_OFFLOAD_TIMESTAMP` flag can be used for this
When the timestamps are enabled, a timestamp validity flag is set in the MBUFs
containing received frames and timestamp is inserted into the `rte_mbuf` struct.

-The timestamp is an `uint64_t` field. Its lower 32 bits represent *seconds* portion of the timestamp
-(number of seconds elapsed since 1.1.1970 00:00:00 UTC) and its higher 32 bits represent
-*nanosecond* portion of the timestamp (number of nanoseconds elapsed since the beginning of the
-second in the *seconds* portion.
+The timestamp is an `uint64_t` field and holds the number of nanoseconds
+elapsed since 1.1.1970 00:00:00 UTC.

Using the NFB PMD
diff --git a/drivers/net/nfb/nfb_rx.h b/drivers/net/nfb/nfb_rx.h
index 12769841ae..67b3b00e2a 100644
--- a/drivers/net/nfb/nfb_rx.h
+++ b/drivers/net/nfb/nfb_rx.h
@@ -13,6 +13,7 @@
#include <rte_mbuf.h>
#include <rte_mbuf_dyn.h>
#include <rte_ethdev.h>
+#include <rte_time.h>

#include "nfb.h"

@@ -202,15 +203,15 @@ nfb_eth_ndp_rx(void *queue,
if (nfb_timestamp_dynfield_offset >= 0) {
rte_mbuf_timestamp_t timestamp;

- /* nanoseconds */
- timestamp =
- rte_le_to_cpu_32(*((uint32_t *)
- (packets[i].header + 4)));
- timestamp <<= 32;
/* seconds */
- timestamp |=
+ timestamp =
rte_le_to_cpu_32(*((uint32_t *)
(packets[i].header + 8)));
+ timestamp *= NSEC_PER_SEC;
+ /* nanoseconds */
+ timestamp +=
+ rte_le_to_cpu_32(*((uint32_t *)
+ (packets[i].header + 4)));
*nfb_timestamp_dynfield(mbuf) = timestamp;
mbuf->ol_flags |= nfb_timestamp_rx_dynflag;
}
--
2.52.0