[dpdk-dev] [PATCH v3 00/33] DPDK Trace support

[Bruce Richardson]

On Wed, Apr 01, 2020 at 09:55:20PM +0530, Jerin Jacob wrote:
> On Wed, Apr 1, 2020 at 7:42 PM David Marchand <david.marchand at redhat.com> wrote:
> >
> > On Wed, Apr 1, 2020 at 12:05 PM Jerin Jacob <jerinjacobk at gmail.com> wrote:
> > > On Wed, Apr 1, 2020 at 1:49 PM David Marchand <david.marchand at redhat.com> wrote:
> > > > - Regardless of the trace framework, the ALLOW_EXPERIMENTAL_API flag
> > > > gates access to APIs so that external users are aware of their status.
> > > > I have been considering setting this flag unconditionally for internal
> > > > users in the top Makefile/meson for app/ lib/ and drivers/.
> > > > I could look at this and prepare a patch about this, but this is not
> > > > enough here.
> > >
> > > It makes sense to me. Let me know when you are planning to send that patch,
> > > I will rebase this series on top of that.
> >
> > Feel free to take over, thanks.
> 
> OK.
> 
> >
> >
> > >
> > > If you don't have time then I can send the patch too.
> > > I assume the patch content will be:
> > > 1) Removing experimental API from app, lib, drivers, examples with
> > > make and meson
> > > 2) Have it enabled at the global level.
> >
> > examples are a special case as they can be compiled out of the dpdk sources.
> > This is why I excluded them of the list in my mail before.
> 
> There are a lot of examples already that have ALLOW_EXPERIMENTAL_API.
> What is the issue in enabling ALLOW_EXPERIMENTAL_API  in the in tree
> example application?
> 
> 
> 
> > >
> > > Since the trace changes in the "inline" functions of the specific
> > > library already
> > > disabled under _compile time_ RTE_ENABLE_TRACE_DP flag and
> > > it is using RTE_TRACE_POINT_DP() to define the trace unlike slow path
> > > trace like RTE_TRACE_POINT().
> >
> > Ah indeed.
> > Note: RTE_ENABLE_TRACE_DP is not plugged with meson.
> 
> If you see the " eal: define the public API for trace support" patch,
> I have updated rte_config.h for meson likewise for other configuration
> such log for DP.
> Would you like to have a meson option? and update in meson_options.txt.
> 
> I don't have a strong opinion on either way? Bruce ,any thoughts?
> 
Since it's likely that developers will be wanting to switch this option on
and off, I think an explicit option rather than hard-coded constant should
be the way to go.

However, an alternative might be to add in the DP tracing for debug builds
but not for others. This would save a build option, but may be more
restrictive, since debug builds can also be optimized ones.

/Bruce