testpmd logging

[Zhang, Yuying]

> -----Original Message-----
> From: Stephen Hemminger <stephen at networkplumber.org>
> Sent: 2022年11月9日 0:40
> To: Owen Hilyard <ohilyard at iol.unh.edu>
> Cc: Honnappa Nagarahalli <Honnappa.Nagarahalli at arm.com>;
> thomas at monjalon.net; Singh, Aman Deep <aman.deep.singh at intel.com>;
> Zhang, Yuying <yuying.zhang at intel.com>; david.marchand at redhat.com;
> dev at dpdk.org; Tu, Lijuan <lijuan.tu at intel.com>; Juraj Linkeš
> <juraj.linkes at pantheon.tech>; nd <nd at arm.com>
> Subject: Re: testpmd logging
> 
> On Tue, 8 Nov 2022 11:24:53 -0500
> Owen Hilyard <ohilyard at iol.unh.edu> wrote:
> 
> > On Tue, Nov 8, 2022 at 9:37 AM Honnappa Nagarahalli <
> > Honnappa.Nagarahalli at arm.com> wrote:
> >
> > > + Lijuan, Owen, Juraj
> > >
> > > > -----Original Message-----
> > > > From: Thomas Monjalon <thomas at monjalon.net>
> > > > Sent: Tuesday, November 8, 2022 7:02 AM
> > > > To: Aman Singh <aman.deep.singh at intel.com>; Yuying Zhang
> > > > <yuying.zhang at intel.com>
> > > > Cc: david.marchand at redhat.com; dev at dpdk.org
> > > > Subject: testpmd logging
> > > >
> > > > Hello,
> > > >
> > > > I see testpmd is doing log with EAL entity. Example:
> > > >       RTE_LOG(ERR, EAL, "The device: %s has been added!\n"
> > > > We could also discuss the log level.
> > > >
> > > > Please can we work on replacing these logs?
> > >
> >
> > If we want to revisit logging in testpmd, even though I know I'm
> > invoking a case of second system syndrome here, I would love to see
> > some form of structured logging output. Even just writing out records
> > to a CSV file with proper escaping would work great, or doing a json
> > object per log record as a backup. JSON might be easier since
> > libjansson is already in DPDK, and we could disable the json logging
> > flag if libjansson was not present at compile time.
> >
> >
> > > DTS uses some of the logs from testpmd to validate the results. I am
> > > not sure what all logs are used.
> >
> >
> > The old version of dts (the one with its own repository) is fairly
> > tightly bound to testpmd's logging.
> >
> > > We need to choose how to log (printf or registered log entity) and
> > > be
> > > > consistent.
> > > > What do you think?
> > >
> >
> > Registered log entries are much better in my opinion since they
> > provide a more machine-friendly format and DTS has to parse testpmd output.
> 
> My thoughts.
>   1. testpmd should use its own log level, not EAL
>   2. testpmd could easily have an option "--json" to format output in JSON
>   3. testpmd is a mess some logs use RTE_LOG() some go to stdout, some to
> stderr.

The same as Hemminger. testpmd should refine log functions then.