Re: The EAL is bloated

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

On Fri, Aug 26, 2022 at 10:58:15AM +0200, Morten Brørup wrote:
> Dear all,
> 
> <rant> The "Environment Abstraction Layer" is expanding far beyond its
> purpose...
> 
> It not only includes abstractions for the underlying CPU Arch and O/S,
> but also a bunch of generic utility functions. In an ideal world, these
> belong in a Utility library; but I can live with them staying in the EAL
> library.
> 
> However, since the Utility features are also considered part of the EAL
> library, some features get misclassified as Utilities and thus sneak into
> the EAL library, regardless that they are completely independent of the
> underlying CPU Arch and O/S. E.g.: Service Cores, Trace, and soon the
> Lcore Poll Busyness library.
> 
> The EAL is not a catch-all library, and we should not allow the EAL to
> grow like this!  </rant>
> 
> If this misbehavior doesn't stop naturally, I propose that adding any new
> feature to the EAL requires techboard approval.
> 
I don't disagree with you that it is indeed becoming ever bigger, and that
we need to do something to do some cleanup on EAL. However, IMHO this is
not a simple problem to fix or even to draft up a solution for. I actually
did some prototyping work in the recent past to try and see if or how much
the EAL could be split up to make it more modular. On the plus side, some
things like logging, for example, could be fairly easily pulled out of it
and put into a separate library. On the other hand, really splitting things
up beyond pulling out a few easy things was a massive undertaking - at
least in my tests.

I also think trying to classify contents between abstractions and utilities
is overly simplistic. To my mind we also need to have a category for DPDK
initialization code, which is a lot of what complicates things - and may
well be the cause of a lot of the "scope creep" in EAL.

Given the scope of the problem - and the fact that splitting EAL has been
discussed before and nothing came of it in the community - I'm not sure of
the best approach here. Maybe we can start by splitting out what we can of
the easy stuff, and work iteratively from there. Alternatively if someone
has time for a big-bang rework of EAL, that would be great too.

Regards,
/Bruce