Re: [PATCH v2 6/6] trace: add PMU

[Bruce Richardson <bruce.richardson@intel.com>]

On Wed, Jun 18, 2025 at 11:47:13AM +0200, Thomas Monjalon wrote:
> 18/06/2025 09:16, Morten Brørup:
> > > diff --git a/lib/meson.build b/lib/meson.build
> > > index 1934cb4a29..87b567f01b 100644
> > > --- a/lib/meson.build
> > > +++ b/lib/meson.build
> > > @@ -13,7 +13,7 @@ libraries = [
> > >          'kvargs', # eal depends on kvargs
> > >          'argparse',
> > >          'telemetry', # basic info querying
> > > -        'pmu',
> > > +        'pmu', # trace depends on pmu
> > >          'eal', # everything depends on eal
> > >          'ptr_compress',
> > >          'ring',
> > 
> > @Tomasz,
> > 
> > Please re-read my v1 review feedback [1]:
> > The PMU library should depend on the EAL, not the other way around!
> 
> It should depend on the low-level EAL, yes.
> But as of now, EAL is not split so it is better to avoid EAL dependency if possible.
> 
> > How else is the PMU library supposed to use EAL functions like rte_mem_page_size()?
> > 
> > @Jerin or @Bruce, do any of you have some suggestions for how to achieve the proper dependency chain here?
> 
> I propose we don't use rte_mem_page_size() in PMU lib for now,
> so we keep not depending on EAL, to avoid mixing all in future.
> Later we could fix it if we manage to have high level EAL as a separate library.
> 
For cases where we only need a single small function or snippet, there is
no problem with circular dependencies if it can be made an inline function
in a header file. We just need to add the appropriate include path to the
build of the PMU library to pick up any EAL headers with inlines.

/Bruce