[dpdk-dev] error in testpmd when CONFIG_RTE_BUILD_SHARED_LIB=y
Bruce Richardson
bruce.richardson at intel.com
Wed Apr 12 12:42:03 CEST 2017
On Wed, Apr 12, 2017 at 11:38:55AM +0100, Bruce Richardson wrote:
> 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 at intel.com>
> > > Cc: Thomas Monjalon <thomas.monjalon at 6wind.com>; john miller
> > > <john.miller at atomicrules.com>; dev at dpdk.org; olivier.matz at 6wind.com
> > > Subject: RE: [dpdk-dev] error in testpmd when CONFIG_RTE_BUILD_SHARED_LIB=y
> > >
> > > > -----Original Message-----
> > > > From: Bruce Richardson [mailto:bruce.richardson at intel.com]
> > > > Sent: Wednesday, April 12, 2017 3:35 PM
> > > > To: Shreyansh Jain <shreyansh.jain at nxp.com>
> > > > Cc: Thomas Monjalon <thomas.monjalon at 6wind.com>; john miller
> > > > <john.miller at atomicrules.com>; dev at dpdk.org; olivier.matz at 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 at 6wind.com]
> > > > > > Sent: Wednesday, April 12, 2017 12:58 AM
> > > > > > To: john miller <john.miller at atomicrules.com>
> > > > > > Cc: dev at dpdk.org; olivier.matz at 6wind.com; Shreyansh Jain
> > > > > > <shreyansh.jain at 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.
>
And as follow-up to my own mail, I think we can actually go further
here. Mempool is a core library, and very little can be done in DPDK
without it. It's also not what most people would think as needing a
driver loaded, so from a usability point of view, I don't see why we
shouldn't link in all mempool drivers by default, like we do other libs.
It will make users life easier, and I can't see any downside to doing
so - they are just .so's after all!
/Bruce
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