Folks,
If one wants/needs to trace packets which vpp creates from whole cloth, here's
how to do it. Typically, it's an input-node function.
/* Top of node dispatch function */
u32 n_trace = vlib_get_trace_count (vm, node);
/* per-buffer */
VLIB_BUFFER_TRACE_TRAJECTORY_INIT (b0);
/* If actually tracing generated packets... */
if (PREDICT_FALSE (n_trace > 0))
{
session_queue_trace_t *t0;
vlib_trace_buffer (vm, node, next_index, b0,
1 /* follow_chain */ );
vlib_set_trace_count (vm, node, --n_trace);
t0 = vlib_add_trace (vm, node, b0, sizeof (*t0));
<fill in rest of trace>
}
In case of interior graph nodes, packets came from somewhere, and should be
traced from where they entered the graph. Otherwise, information is lost.
Thanks... Dave
From: vpp-dev-boun...@lists.fd.io [mailto:vpp-dev-boun...@lists.fd.io] On
Behalf Of Luke, Chris
Sent: Thursday, July 13, 2017 6:51 AM
To: yug...@telincn.com; vpp-dev <vpp-dev@lists.fd.io>
Subject: Re: [vpp-dev] trace
Ewan,
Yes, it only works on the device input nodes. You're the second person to ask
this recently, I guess we need to add a note to some documentation somewhere. :)
Cheers,
Chris
From: vpp-dev-boun...@lists.fd.io<mailto:vpp-dev-boun...@lists.fd.io>
[mailto:vpp-dev-boun...@lists.fd.io] On Behalf Of
yug...@telincn.com<mailto:yug...@telincn.com>
Sent: Thursday, July 13, 2017 0:41
To: vpp-dev <vpp-dev@lists.fd.io<mailto:vpp-dev@lists.fd.io>>
Subject: [vpp-dev] trace
Hi all,
Cmd "vppctl trace add" only work for input nodes? Such as "dpdk-input" and
"af-packet-input".
I found out that cmd "vppctl trace add ip4-input 1000" doesn't work.
Regards,
Ewan
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