[dpdk-dev] [PATCHv6 16/33] drivers/pool/dpaa2: adding hw offloaded mempool

[Neil Horman]

On Tue, Jan 24, 2017 at 06:28:59PM +0100, Thomas Monjalon wrote:
> 2017-01-24 20:07, Hemant Agrawal:
> > On 1/24/2017 4:19 PM, Ferruh Yigit wrote:
> > > On 1/24/2017 9:12 AM, Shreyansh Jain wrote:
> > >> On Monday 23 January 2017 11:04 PM, Ferruh Yigit wrote:
> > >>> On 1/23/2017 11:59 AM, Hemant Agrawal wrote:
> > >>>> +# library dependencies
> > >>>> +DEPDIRS-$(CONFIG_RTE_LIBRTE_DPAA2_POOL) += lib/librte_eal
> > >>>> +DEPDIRS-$(CONFIG_RTE_LIBRTE_DPAA2_POOL) += lib/librte_mempool
> > >>>> +DEPDIRS-$(CONFIG_RTE_LIBRTE_DPAA2_POOL) += lib/librte_common_dpaa2_qbman
> > >>>
> > >>> This dependeny doesn not looks correct, there is no folder like that.
> > >>
> > >> This is something even I need to understand. From the DEPDIRS what I
> > >> understood was that though it refers to a directory, it essentially
> > >> links libraries in build/lib/*.
> > >>
> > >> Further, somehow the development is deploying drivers/bus,
> > >> drivers/common and drivers/pool in lib/* under the name specified as
> > >> LIB in Makefile. My understanding was that it is expected behavior and
> > >> not special because of drivers folder.
> > >>
> > >> Thus, above line only links lib/librte_common_dpaa2_qbman generated by
> > >> drivers/common/dpaa2/qbman code.
> > >>
> > >> In fact, I think, this might also one of the issues why a parallel
> > >> shared build fails for DPAA2 PMD (added in Cover letter).
> > >> The dependency graph cannot create a graph for drivers/common
> > >> as dependency for drivers/net or drivers/bus and hence parallel build
> > >> fails because of missing libraries which are being parallely compiled.
> > >
> > > DEPDIRS-y is mainly to resolve dependencies for compilation order, and
> > > should point to the folder,
> > >
> > > Following line will cause "librte_eal" to be compiled before driver:
> > > DEPDIRS-$(CONFIG_RTE_LIBRTE_DPAA2_POOL) += lib/librte_eal
> > >
> > > So "lib/librte_common_dpaa2_qbman" does not makes more sense, since
> > > there is no folder like that.
> > >
> > >
> > > Somewhere in the history, with following commit, DEPDIRS-y gained a side
> > > effect, it has been used to set dynamic linking dependencies, to fix
> > > underlinking issue:
> > >  bf5a46fa5972 ("mk: generate internal library dependencies")
> > >
> > > I guess you are having that line to benefit from this side effect, but
> > > this can be done with following more properly:
> > > LDLIBS += lib/librte_common_dpaa2_qbman
> > >
> > >
> > > To resolve the drivers/net to drivers/common dependency, following line
> > > in this Makefile should work:
> > > DEPDIRS-$(CONFIG_RTE_LIBRTE_DPAA2_PMD) += drivers/common/dpaa2
> > >
> > > This adds following, which will cause "drivers/common" compiled before
> > > any "drivers/net":
> > > LOCAL_DEPDIRS-drivers/net += drivers/common
> > 
> > Thanks for your suggestion. This is one thing, I am not yet able to fix.
> > 
> > Based on your suggestions:
> > e.g.
> > LDLIBS += -lrte_common_dpaa2_qbman
> > DEPDIRS-$(CONFIG_RTE_LIBRTE_FSLMC_BUS) += drivers/common/dpaa2
> > 
> > It does add entry in the ".depdirs"
> > ./arm64-dpaa2-linuxapp-gcc/.depdirs:168:LOCAL_DEPDIRS-drivers/bus += 
> > drivers/common
> > ./arm64-dpaa2-linuxapp-gcc/.depdirs:170:LOCAL_DEPDIRS-drivers += lib
> > ./arm64-dpaa2-linuxapp-gcc/.depdirs:172:LOCAL_DEPDIRS-drivers += lib
> > ./arm64-dpaa2-linuxapp-gcc/.depdirs:174:LOCAL_DEPDIRS-drivers/pool += 
> > drivers/common
> > 
> > However,  we keep on getting:
> > LD librte_bus_fslmc.so.1.1
> > aarch64-linux-gnu-gcc: error: drivers/common/dpaa2: No such file or 
> > directory
> > make[6]: *** [librte_bus_fslmc.so.1.1] Error 1
> 
> Probably because of:
> 
> # Translate DEPDIRS-y into LDLIBS
> # Ignore (sub)directory dependencies which do not provide an actual library
> _IGNORE_DIRS = lib/librte_eal/% lib/librte_compat
> _DEPDIRS = $(filter-out $(_IGNORE_DIRS),$(DEPDIRS-y))
> _LDDIRS = $(subst librte_ether,librte_ethdev,$(_DEPDIRS))
> LDLIBS += $(subst lib/lib,-l,$(_LDDIRS))
> 
> It shows one important thing: qbman is not a driver, it is a lib.
> So drivers/common/dpaa2 should be handled differently.
> 
> Solution 1: tweak mk/rte.lib.mk for directories in drivers/common/
> Solution 2: host your bus libs outside of DPDK
Please do not go with suggestion two, the more libraries get hosted outside of
the project, the less likely any sort of test/build/ongoing maintenence from the
community can be expected.  If you're going to go with solution (2), then you
may as well host the entire PMD outside of the DPDK project, and thats more
undesireable.

Neil

>