10/11/2020 15:19, Bruce Richardson: > On Tue, Nov 10, 2020 at 02:53:03PM +0100, Thomas Monjalon wrote: > > 10/11/2020 14:19, Bruce Richardson: > > > On Tue, Nov 10, 2020 at 02:04:21PM +0100, Thomas Monjalon wrote: > > > > 10/11/2020 12:34, Bruce Richardson: > > > > > On Tue, Nov 10, 2020 at 12:25:13PM +0100, Thomas Monjalon wrote: > > > > > > 10/11/2020 11:08, Bruce Richardson: > > > > > > > On Mon, Nov 09, 2020 at 08:26:10PM +0100, Thomas Monjalon wrote: > > > > > > > > 09/11/2020 19:02, Bruce Richardson: > > > > > > > > > On Mon, Nov 09, 2020 at 06:09:51PM +0100, Thomas Monjalon > > > > > > > > > wrote: > > > > > > > > > > 27/10/2020 18:38, Bruce Richardson: > > > > > > > > > > > To test the installation process of DPDK using "ninja > > > > > > > > > > > install" > > > > > > > > > > > test-meson-builds.sh builds a subset of the examples > > > > > > > > > > > using "make". > > > > > > > > > > > To allow more flexibility for people testing, allow the > > > > > > > > > > > set of > > > > > > > > > > > examples chosen for this make test to be overridden using > > > > > > > > > > > variable > > > > > > > > > > > "DPDK_BUILD_TEST_EXAMPLES" in the environment. > > > > > > > > > > > > > > > > > > > > > > Since a number of example apps link against drivers > > > > > > > > > > > directly even > > > > > > > > > > > for shared builds, we need to ensure that LD_LIBRARY_PATH > > > > > > > > > > > points to > > > > > > > > > > > the main DPDK lib folder so any dependencies of those > > > > > > > > > > > drivers can > > > > > > > > > > > be found e.g. that the PCI/vdev bus driver .so is found. > > > > > > > > > > > [All > > > > > > > > > > > drivers are symlinked from drivers dir back to lib dir on > > > > > > > > > > > install, > > > > > > > > > > > so only one dir rather than two is needed in the path.] > > > > > > > > > > [...] > > > > > > > > > > > +libdir=$(dirname $(find $DESTDIR -name librte_eal.so)) > > > > > > > > > > > +export > > > > > > > > > > > LD_LIBRARY_PATH=$libdir:$LD_LIBRARY_PATH > > > > > > > > > > > > > > > > > > > > I don't get why libdir is required for some examples, and > > > > > > > > > > not for > > > > > > > > > > others? The pkg-config file is not enough? > > > > > > > > > > > > > > > > > > > > > > > > > > > > It's only needed for examples that link against drivers > > > > > > > > > directly. > > > > > > > > > > > > > > > > > > I believe it's needed in those cases, because app linker flags > > > > > > > > > (including e.g. -lrte_pmd_bond) occur before the pkg-config > > > > > > > > > flags, > > > > > > > > > which means that the linker at that point does not have the > > > > > > > > > path to > > > > > > > > > find the dependencies of the driver. [In a normal build, this > > > > > > > > > wouldn't > > > > > > > > > be necessary because the library directory would be a > > > > > > > > > standard path] > > > > > > > > > > > > > > > > If it's just a matter of ordering, it would be a better example > > > > > > > > to fix > > > > > > > > the ordering in the Makefile, isn't it? > > > > > > > > > > > > > > > > > > > > > > I thought about that, but it seems strange to have the DPDK > > > > > > > linker flags > > > > > > > appear before the application specific flags. The general style > > > > > > > is to have > > > > > > > the apps own linker flags apply first, and then the list of > > > > > > > dependencies, > > > > > > > so that any app linker flags take precedence. The other option is > > > > > > > to have > > > > > > > two separate LDFLAG variables for the app, one for before > > > > > > > pkg-config flags > > > > > > > and the other afterwards, but that is an untidy solution. > > > > > > > > > > > > > > Therefore, I think it's better to keep the ordering in the > > > > > > > examples as-is > > > > > > > and just set the library path in the script. It's only a single > > > > > > > extra > > > > > > > assignment that is necessary because we are installing to a > > > > > > > non-standard > > > > > > > path using DESTDIR. > > > > > > > > > > > > It is OK to add LD_LIBRARY_PATH in test-meson-builds.sh because > > > > > > DPDK is "installed" with a DESTDIR prefix. > > > > > > > > > > > > But this change is unrelated to test more examples, > > > > > > it is a general fix for examples compilation. > > > > > > The thing I'm missing, as I said above, > > > > > > "why libdir is required for some examples, and not for others?" > > > > > > I feel something wrong made linking work where it should not. > > > > > > > > > > > > > > > > As I explained above, libdir is required for examples that link > > > > > directly > > > > > against DPDK drivers in shared builds. There are only a few examples > > > > > that > > > > > do so, which is why the majority worked fine, and why this was not > > > > > needed > > > > > before. > > > > > > > > Sorry I don't understand how we link other libraries without > > > > LD_LIBRARY_PATH. > > > > Where the library path was taken from before this change? > > > > > > > > > > pkg-config outputs the library path via -L flag for all the other > > > libraries, which is why they are picked up. Right now the flags passed > > > are > > > (in the case of the bonding example app): > > > > > > LDFLAGS += -lrte_net_bond > > > ... > > > LDFLAGS_SHARED = $(shell $(PKGCONF) --libs libdpdk) > > > ... > > > build/$(APP)-shared: $(SRCS-y) Makefile $(PC_FILE) | build > > > $(CC) $(CFLAGS) $(SRCS-y) -o $@ $(LDFLAGS) $(LDFLAGS_SHARED) > > > > > > which resolves to (roughly): > > > "-lrte_net_bond -L/path/to/dpdk/libs -lrte_ethdev ..." > > > > This is the part I still don't understand. > > How it can resolve to path including DESTDIR? > > In my test, it resolves to -L/usr/local/lib so it cannot work. > > > It's the --define-prefix parameter we pass to pkg-config that does the > trick. > > $ export > PKG_CONFIG_LIBDIR=$(pwd)/usr/local/lib/pkgconfig:/usr/lib/x86_64-linux-gnu/pkgconfig > > $ pkg-config --libs-only-L libdpdk > -L/usr/local/lib -L/usr/lib/x86_64-linux-gnu > > $ pkg-config --define-prefix --libs-only-L libdpdk > -L/home/bruce/dpdk.org/__BUILDS/build-x86-default/install/usr/local/lib > -L/usr/lib/lib/x86_64-linux-gnu > > This is done in test-meson-builds right before we call make for each > example: > > # if pkg-config defines the necessary flags, test building some examples > if pkg-config --define-prefix libdpdk >/dev/null 2>&1; then > export PKGCONF="pkg-config --define-prefix" > ... > fi
Yes this is what David suggested to me, but it doesn't work well for me (while test-meson-builds.sh works): PKG_CONFIG_PATH=../dpdk-build/build-x86-default/meson-private \ pkg-config --define-prefix --libs-only-L libdpdk -L/usr/local/lib Oh! I am testing on the build directory instead of installed one. PKG_CONFIG_PATH=../dpdk-build/build-x86-default/install/usr/local/lib/pkgconfig \ pkg-config --define-prefix --libs-only-L libdpdk -L../dpdk-build/build-x86-default/install/usr/local/lib Good :) Now THE question: what is the difference between these two .pc files?
