[dpdk-dev] [PATCH 00/39] adding eventmode helper library

[Jerin Jacob Kollanukkaran]

> -----Original Message-----
> From: Anoob Joseph
> Sent: Thursday, June 20, 2019 9:15 AM
> To: Mattias Rönnblom <mattias.ronnblom at ericsson.com>; Jerin Jacob
> Kollanukkaran <jerinj at marvell.com>; Nikhil Rao <nikhil.rao at intel.com>; Erik
> Gabriel Carrillo <erik.g.carrillo at intel.com>; Abhinandan Gujjar
> <abhinandan.gujjar at intel.com>; Bruce Richardson
> <bruce.richardson at intel.com>; Pablo de Lara
> <pablo.de.lara.guarch at intel.com>
> Cc: Narayana Prasad Raju Athreya <pathreya at marvell.com>; dev at dpdk.org;
> Lukas Bartosik <lbartosik at marvell.com>; Pavan Nikhilesh Bhagavatula
> <pbhagavatula at marvell.com>; Hemant Agrawal <hemant.agrawal at nxp.com>;
> Nipun Gupta <nipun.gupta at nxp.com>; Harry van Haaren
> <harry.van.haaren at intel.com>; Liang Ma <liang.j.ma at intel.com>
> Subject: RE: [dpdk-dev] [EXT] Re: [PATCH 00/39] adding eventmode helper
> library
> > However, the flexibility and many of the parameters are there for a
> > reason (those there aren't should be deprecated). I would expect a
> > real-world application to tweak quite a few of them. I know our applications
> do.
> >
> > I worry I have is that if you put eventmode (in its current form)
> > forward as a generic framework, applications might start using it,
> > only to realize it's not flexible enough, and then eventmode is just
> > an extra layer, increasing rather than reducing complexity. Or even
> > worse, the application's developers are forced to do a big-bang switch
> > over to using the event and ethernet device APIs directly, in case
> > they can't patch DPDK to work around the eventmode- assumption-that-
> didn't-hold-for-them.
> >
> > You could always add flexibility to the framework (as you encounter a
> > need for it), but then it will grow in complexity as well.
> >
> > A less ambitious approach would be to instead do a properly
> > modularized, non-trivial eventdev example application, for the
> > applications to start off from, instead of a generic library.
> >
> > I would expect it to be very difficult to design a truly generic
> > application framework for eventdev-based applications. Such a
> > framework would tie everything that's needed in a non-trivial
> > application together. If successful, it would be a huge step toward
> > making DPDK an operating system for packet processing applications.
> 
> [Anoob] The idea here is not to deprecate any event dev APIs. I do agree that all
> the configuration exposed by eventdev & adapters are required for various
> requirements in the real world applications. But the requirement to understand
> & use all this configuration is making the applications complicated and causes
> significant effort from anyone who would want to get started with event mode.
> The idea of helper is to allow an easy framework for applications to get started
> with eventmode, and then use various options from C/L or config file (both
> planned) to override the configuration as required. DPDK has components like
> crypto-scheduler which abstracts lot of configuration and simplify usage from
> application's perspective. This effort is on similar lines.
> 
> My patchset is a followup to http://patches.dpdk.org/patch/37955 , wherein the
> approach of introducing a helper library for event mode was mooted. The initial
> patch proposed additions in one application, and that involved huge code
> additions just for doing the configuration.
> 
> The helper library will be experimental while we add event-mode support for
> other applications like l3fwd & ipsec-secgw. I expect the helper library to be
> complete over the course of those applications also using the helper library.


I have only concern about moving this as library inside eventdev that till we have mature
version of helper library the eventdev library ABI will not stable(i.e .so file version needs
to be incremented as when a change needed). Which align with Mattias thoughts for
some other reason:. How about moving this code to
1) example/common or
2) to specific application itself, once at least two applications starts using it then move
to Eventdev library.

Thoughts?




> 
> >
> > What event devices have you tested with?
> 
> [Anoob] Eventmode helper is tested with the following combinations,
>     1. event-octeontx event PMD & nicvf eth PMD
>     2. event-octeontx event PMD & eth-octeontx eth PMD