[dpdk-users] Time-stamping from 18.05 to 19.02

[Filip Janiszewski <contact@filipjaniszewski.com>]

Hi,

In order to understand how DPDK handle HW timestamps (which is very
confusing between version) I've prepare a small DPDK test application
which capture packets on a give port and print some information, like
pkt_len, timestamp etc - very basic stuff.

I've enabled the offload DEV_RX_OFFLOAD_TIMESTAMP at port/queue level,
and built the application with DPDK 18.05.

The captured packets are valid and although the hardware timestamp is
crappy I still can see something, example output:

"queue 1, len 139, timestamp (1) 55659417086261"

from:

.
fprintf(stderr,"queue %d, len %"PRIu32", timestamp (%d) %"PRIu64,
queue_idx,
pkt_bufs[0]->pkt_len,
( int )( 0 != ( pkt_bufs[0]->ol_flags & PKT_RX_TIMESTAMP ) ),
pkt_bufs[0]->timestamp);
.

(Where pkt_bufs is an array of mbufs, there is a check before the
fprintf that verify something has been captured, so the code is "safe"..
but ugly (hey, that's a test app after all..)

The PKT_RX_TIMESTAMP flag is set, which make sense..

Then i switched to DPDK 19.02 and recompiled, the only change in the
code that was required was to remove the line where i set hw_timestamp
to 1 in rte_eth_rxmode, this field does not exist anymore.

With this new DPDK the packets are not coming with any timestamp and
PKT_RX_TIMESTAMP in ol_flags is not set, what has changed between those
two DPDK relase (major vs stable) and what should I do to enable
timestamping?

Thanks

-- 
BR, Filip
+48 666 369 823