Re: [dpdk-dev] [PATCH v4 00/33] DPDK Trace support

[Thomas Monjalon <thomas@monjalon.net>]

Hi,

03/04/2020 17:36, jerinj@marvell.com:
> Features:
> ~~~~~~~~~
> - APIs and Features are similar to rte_log dynamic framework
> API(expect log prints on stdout vs it dumps on trace file)

A log can print to syslog as well.

As discussed somewhere else, please do not introduce global level
in rte_trace. I think it is useless. If we need to change the level
of all trace types, we can just use a wildcard (globbing or regexp).

And about wording, "pattern" is too vague and should be replaced
with "globbing".


> - No specific limit on the events. A string-based event like rte_log
> for pattern matching

Would it be possible to replace rte_log with rte_trace?


> - Dynamic enable/disable support.

How dynamic it is? Can we start/stop a trace after starting DPDK?
I think we need a control channel for this.
I propose to introduce a general control channel in DPDK.


> - Instructmention overhead is ~1 cycle. i.e cost of adding the code

Nice


> wth out using trace feature.
> - Timestamp support for all the events using DPDK rte_rtdsc

Could we use other timestamp sources, like the mbuf timestamp
for Rx traces?


> - No dependency on another library. Clean room native implementation of
>   CTF.

No benefit of using an external CTF library maintained somewhere else?