Re: error in testpmd when CONFIG_RTE_BUILD_SHARED_LIB=y

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

On Wed, Apr 12, 2017 at 10:33:10AM +0000, Shreyansh Jain wrote:
> My bad - I was too quick in replying - some clarification beneath.
> 
> > -----Original Message-----
> > From: Shreyansh Jain
> > Sent: Wednesday, April 12, 2017 3:55 PM
> > To: 'Bruce Richardson' <bruce.richardson@intel.com>
> > Cc: Thomas Monjalon <thomas.monjalon@6wind.com>; john miller
> > <john.miller@atomicrules.com>; dev@dpdk.org; olivier.matz@6wind.com
> > Subject: RE: [dpdk-dev] error in testpmd when CONFIG_RTE_BUILD_SHARED_LIB=y
> > 
> > > -----Original Message-----
> > > From: Bruce Richardson [mailto:bruce.richardson@intel.com]
> > > Sent: Wednesday, April 12, 2017 3:35 PM
> > > To: Shreyansh Jain <shreyansh.jain@nxp.com>
> > > Cc: Thomas Monjalon <thomas.monjalon@6wind.com>; john miller
> > > <john.miller@atomicrules.com>; dev@dpdk.org; olivier.matz@6wind.com
> > > Subject: Re: [dpdk-dev] error in testpmd when CONFIG_RTE_BUILD_SHARED_LIB=y
> > >
> > > On Wed, Apr 12, 2017 at 04:52:47AM +0000, Shreyansh Jain wrote:
> > > > > -----Original Message-----
> > > > > From: Thomas Monjalon [mailto:thomas.monjalon@6wind.com]
> > > > > Sent: Wednesday, April 12, 2017 12:58 AM
> > > > > To: john miller <john.miller@atomicrules.com>
> > > > > Cc: dev@dpdk.org; olivier.matz@6wind.com; Shreyansh Jain
> > > > > <shreyansh.jain@nxp.com>
> > > > > Subject: Re: [dpdk-dev] error in testpmd when
> > > CONFIG_RTE_BUILD_SHARED_LIB=y
> > > > >
> > > > > 2017-04-11 14:02, john miller:
> > > > > >
> > > > > > We are seeing an issue when running from the head of the master
> > branch
> > > in
> > > > > dpdk-next-net and building with CONFIG_RTE_BUILD_SHARED_LIB=y.   When
> > we
> > > run
> > > > > testpmd using  -d to point to our PMD we get this error
> > > > > >
> > > > > > EAL: Error - exiting with code: 1
> > > > > >   Cause: Creation of mbuf pool for socket 0 failed: Invalid argument
> > > > > >
> > > > > > This error occurs as a result of the rte mempool ops table having 0
> > > > > entries.  This table is populated from a call to
> > > rte_mempool_register_ops().
> > > > > This function gets called in rte_mempool_ring.c via the static
> > > initialization
> > > > > MACRO MEMPOOL_REGISTER_OPS and exists in librte_mempool_ring.so.
> > However
> > > > > this library is not loaded when the rte_eal_init() gets called so the
> > > static
> > > > > initializers are not yet loaded.
> > > > > >
> > > > > > I am requesting advice on the proper way to repair this.
> > > >
> > > > "-d" the ring library (rte_mempool_ring) - just like any other shared
> > lib.
> > > >
> > >
> > > I think this is a bug that should be fixed. The user should not need to
> > > have to specify a mempool driver just to get testpmd working, so I think
> > > the ring handler as default should be compiled in automatically so as to
> > > allow regular mempools to just work as before.
> > 
> > For Ring Mempool as default enabled, +1
>  
> Actually, Ring mempool is enabled by default. But, obviously for shared library case, this still means "-d".
> 

Not necessarily. That only applies if we don't explicitly link it like
the other shared libraries. We "special-case" our drivers in that we
don't add them with a -l flag, but expect the user to dynamically load
them at runtime. This is one case where I think all apps should
explicitly link against the ring mempool driver. There is no reason we
can't make some drivers mandatory.

> > 
> > >
> > > > This change was done recently to move ring handler into its separate
> > > drivers/mempool/ring directory. That also means it no longer is compiled
> > into
> > > the librte_mempool.
> > > >
> > > > >
> > > > > We should just add a better error message if no mempool driver is
> > > available.
> > > >
> > > > Yes, that is something to be improved.
> > >
> > > This should be fixed by always having a mempool driver installed.
> > 
> > Agree.
>  
> Probably, as ring mempool is a driver and compiled in shared mode, enabled by default will not fix this.

But linked in by default will fix it.

/Bruce