On Wed, 2018-11-14 at 17:40 +0000, Burdick, Cliff wrote: > > -----Original Message----- > From: Bruce Richardson [mailto:bruce.richard...@intel.com] > Sent: Wednesday, November 14, 2018 3:48 AM > To: Burdick, Cliff > Cc: Thomas Monjalon; Burakov, Anatoly; dev@dpdk.org > Subject: Re: [dpdk-dev] [PATCH 1/1] eal: Don't fail secondary if > primary is missing tailqs > > On Tue, Nov 13, 2018 at 11:42:51PM +0000, Burdick, Cliff wrote: > > > > > > ________________________________________ > > > From: Thomas Monjalon [tho...@monjalon.net] > > > Sent: Tuesday, November 13, 2018 2:18 PM > > > To: Burdick, Cliff > > > Cc: Burakov, Anatoly; dev@dpdk.org; bruce.richard...@intel.com > > > Subject: Re: [dpdk-dev] [PATCH 1/1] eal: Don't fail secondary if > > > primary is missing tailqs > > > > > > 13/11/2018 23:08, Burdick, Cliff: > > > > From: Thomas Monjalon [mailto:tho...@monjalon.net] > > > > > 13/11/2018 17:38, Burdick, Cliff: > > > > > > From: Thomas Monjalon [mailto:tho...@monjalon.net] > > > > > > 13/11/2018 16:45, Burdick, Cliff: > > > > > > > From: Burakov, Anatoly [mailto:anatoly.bura...@intel.com] > > > > > > > > On 13-Nov-18 9:21 AM, Thomas Monjalon wrote: > > > > > > > > > 13/11/2018 00:33, Burdick, Cliff: > > > > > > > > > > This patch was submitted by Jean Tourrilhes over > > > > > > > > > > two > > > > > > > > > > years ago, but didn't receive any responses. I hit > > > > > > > > > > the > > > > > > > > > > same issue recently when trying to use cgo (Golang) > > > > > > > > > > as a > > > > > > > > > > primary process linked to libdpdk.a against a C++ > > > > > > > > > > application linked against the same library.> > > > > > > > > > > > > > > > > > > > > The question is to know why you don't have the same > > > > > > > > > constructors in primary and seconday? > > > > > > > > > > > > > > > > I've hit similar things in the past. I believe it was > > > > > > > > caused > > > > > > > > by our build system stripping out unused libraries > > > > > > > > (such as > > > > > > > > rte_hash) from the binary and thus not calling the > > > > > > > > constructor in the primary, but doing so in the > > > > > > > > secondary > > > > > > > > (or something to that effect). In any case, this is > > > > > > > > caused > > > > > > > > by linking different number of libraries to primary > > > > > > > > and > > > > > > > > secondary, and should probably be fixed in the build > > > > > > > > system, > > > > > > > > not in the tailqs code (unless we specifically support > > > > > > > > having different linked libraries to primary and > > > > > > > > secondary?).> > > > > > > > > > > > > > > > > > Right, I think the original author of the patch stated > > > > > > > the > > > > > > > reasons in the link I provided. The build system seems > > > > > > > like > > > > > > > the most appropriate place to fix it, but the patch got > > > > > > > me > > > > > > > going quickly. I think the question is whether you want > > > > > > > DPDK > > > > > > > to support these other ways of linking. I'm certainly not > > > > > > > the > > > > > > > first to use cgo, since there's a virtual switch project > > > > > > > doing the same: > > > > > > > > > > > > > > https://urldefense.proofpoint.com/v2/url?u=https-3A__gith > > > > > > > ub.co > > > > > > > m_lago > > > > > > > pu > > > > > > > s_vsw&d=DwICAg&c=jcv3orpCsv7C4ly8- > > > > > > > ubDoUfrxF5xIGWmptxGWP5vi5w&r > > > > > > > =m1RLQ > > > > > > > OG > > > > > > > Okz9MauvVLZmiGtyWc5mA7DejbPFNE1IDj- > > > > > > > 4&m=hQqVCNwW7eoEzB_hLFK97i8 > > > > > > > idS8FI qX > > > > > > > oPeclwsIZq7Y&s=BMoBlwkqljwWIBY3SE3pPMCfVnOUlDuZLrno4- > > > > > > > SojKM&e= > > > > > > > > > > > > > > They don't use primary/secondary processes, though, so > > > > > > > the > > > > > > > issue is never hit. I'm in a situation where using cgo > > > > > > > seemed > > > > > > > like the easiest path to accomplish what I'm doing since > > > > > > > I > > > > > > > needed specialized libraries for it that were not > > > > > > > available in > > > > > > > C/C++. At some point I bet someone would use Cython to > > > > > > > start > > > > > > > linking against DPDK as well, and we'd likely run into > > > > > > > the > > > > > > > same issue.> > > > For sure, we want to support using > > > > > > > DPDK with cgo or cython. > > > > > > > But it is not clear what is the relation with not having > > > > > > > the > > > > > > > same compilation for primary and secondary. Please could > > > > > > > you > > > > > > > elaborate?> > > > > > > > > > > > > > > Hi Thomas, I think Jean explained it well here: > > > > > > https://urldefense.proofpoint.com/v2/url?u=https-3A__dev.dp > > > > > > dk.narkive. > > > > > > com_ZM3a7QD1_dpdk-2Ddev-2Dbug-2Dstatic-2Dconstructors- > > > > > > 2Dconsider > > > > > > ed-2De > > > > > > vil&d=DwICAg&c=jcv3orpCsv7C4ly8- > > > > > > ubDoUfrxF5xIGWmptxGWP5vi5w&r=m1R > > > > > > LQOGOk > > > > > > z9MauvVLZmiGtyWc5mA7DejbPFNE1IDj- > > > > > > 4&m=C69wDgrjDX8_oXp1M_3bnmWOOZd > > > > > > GqwBBG > > > > > > 9vzkyGDWGQ&s=YYn2N7WrzJpH1ptNrLZad0nPAQdrUyqBckk2uFuWYPQ&e= > > > > > > > > > > > > "The build system of the application does not have all the > > > > > > subtelties of the DPDK build system, and ends up including > > > > > > *all* > > > > > > the constructors, wether they are used or not in the code. > > > > > > Moreover, they are included in a different order. Actually, > > > > > > by > > > > > > default the builds include no constructors at all (which is > > > > > > a > > > > > > big fail), so the library needs to be included with > > > > > > --whole-archive (see Snort DPDK instructions)." > > > > > > > > > > > > I will get to the bottom of my exact case to understand > > > > > > what's > > > > > > happening, but my primary application is a cgo application > > > > > > that > > > > > > I'm linking to by using almost exactly the same flags that > > > > > > are > > > > > > used in the DPDK build system to build examples. The DPDK > > > > > > libraries I'm linking against is a single location for > > > > > > both > > > > > > primary and secondary; in other words, I don't build DPDK > > > > > > twice. > > > > > > > > > > > > OK I understand, thanks. > > > > > > > > > > > > You had alluded to a pkg-config for DPDK in the 2015 > > > > > > thread, > > > > > > which cgo can use, but I don't know if that ever was > > > > > > implemented. Cgo can use pkg-config if it's available, > > > > > > otherwise > > > > > > the only tools are specifying LDFLAGS and CFLAGS into their > > > > > > build system. > > > > > > > > > > Yes, the right answer is still pkg-config :) The good news is > > > > > that it is now implemented thanks to the meson build system: > > > > > > > > > > https://urldefense.proofpoint.com/v2/url?u=http-3A__git.dpdk. > > > > > org_dp > > > > > dk_tree_doc_build-2Dsdk-2Dmeson.txt- > > > > > 23n182&d=DwICAg&c=jcv3orpCsv7C4 > > > > > ly8- > > > > > ubDoUfrxF5xIGWmptxGWP5vi5w&r=m1RLQOGOkz9MauvVLZmiGtyWc5mA7Dej > > > > > bP > > > > > FNE1IDj- > > > > > >4&m=C69wDgrjDX8_oXp1M_3bnmWOOZdGqwBBG9vzkyGDWGQ&s=oC86KD_R > > > > > J1T6rfzi3x5zFT1Ri13ELpKmsyFqpgDbgFg&e= > > > > > > > > Hi Thomas, are there instructions on how to use pkg-config to > > > > build the mlx4/5 PMD? I noticed a patch was submitted in > > > > September to add support for it, but that link you provided on > > > > using meson doesn't say how to build specific drivers. It > > > > appears to be disabled by default. > > > > If the dependency is found, meson will enable the PMD when > > > > building DPDK. > > > > > > Do you know where exactly that is? I've been using mlx5 for a > > > while on this system, and I can see that 18.11-rc2 meson > > > build+ninja built the pmd, but it's not on the --libs listing for > > > pkg-config. Does it tell me what I was missing? > > > > > > > For dynamic linking of applications, the drivers are not normally > > linked in. Instead, they should be loaded from the drivers > > directory as .so files > > - normally by default in EAL as the driver .so's should be copied > > to the EAL_PMD_PATH where EAL finds them automatically. [This > > applies to both meson and make builds, though only meson generates > > the .pc file for pkg-config] > > > > If you are doing a static build, then you need to explicitly link > > in the drivers. You can get a list from pkg-config using the " > > --static" flag in this case. A good example of how to use pkg- > > config in this way can be found in the Makefiles for most examples, > > e.g. examples/helloworld/Makefile, reproduced below. > > > > Regards, > > /Bruce > > > > all: shared > > .PHONY: shared static > > shared: build/$(APP)-shared > > ln -sf $(APP)-shared build/$(APP) > > static: build/$(APP)-static > > ln -sf $(APP)-static build/$(APP) > > > > PC_FILE := $(shell pkg-config --path libdpdk) CFLAGS += -O3 $(shell > > pkg-config --cflags libdpdk) LDFLAGS_SHARED = $(shell pkg-config -- > > libs libdpdk) LDFLAGS_STATIC = -Wl,-Bstatic $(shell pkg-config -- > > static --libs libdpdk) > > > > build/$(APP)-shared: $(SRCS-y) Makefile $(PC_FILE) | build > > $(CC) $(CFLAGS) $(SRCS-y) -o $@ $(LDFLAGS) > > $(LDFLAGS_SHARED) > > > > build/$(APP)-static: $(SRCS-y) Makefile $(PC_FILE) | build > > $(CC) $(CFLAGS) $(SRCS-y) -o $@ $(LDFLAGS) > > $(LDFLAGS_STATIC) > > > > build: > > @mkdir -p $@ > > Thanks Bruce. I tried getting this to compile using cgo, and it's > causing more pain than it's worth. I used the --static --libs > options, and there were still numerous linker errors, some specific > to mlx, and some not. Specifically libmlx5 and libmnl are both > needed, but they're not part of the linker line from pkg-config. At > this point I'll just break the Go application up into a separate C > application that handles all the DPDK parts, and send messages > between them.
Hi, As far as I can see, both mnl and mlx5 (and all the other reverse dependencies) are listed correctly in the libdpdk.pc Libs.private entry, and pkg-config --libs --static libdpdk.pc does print them as intended. This is with 18.11-rc3. Are you sure everything is correct (pkg-config path is right, --static is used, etc)? -- Kind regards, Luca Boccassi