________________________________________ 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__github.com_lago > > > > pu > > > > s_vsw&d=DwICAg&c=jcv3orpCsv7C4ly8-ubDoUfrxF5xIGWmptxGWP5vi5w&r=m1RLQ > > > > OG > > > > Okz9MauvVLZmiGtyWc5mA7DejbPFNE1IDj-4&m=hQqVCNwW7eoEzB_hLFK97i8idS8FI > > > > 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.dpdk.narkive. > > > com_ZM3a7QD1_dpdk-2Ddev-2Dbug-2Dstatic-2Dconstructors-2Dconsidered-2De > > > vil&d=DwICAg&c=jcv3orpCsv7C4ly8-ubDoUfrxF5xIGWmptxGWP5vi5w&r=m1RLQOGOk > > > z9MauvVLZmiGtyWc5mA7DejbPFNE1IDj-4&m=C69wDgrjDX8_oXp1M_3bnmWOOZdGqwBBG > > > 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_dpdk_tree_doc_build-2Dsdk-2Dmeson.txt-23n182&d=DwICAg&c=jcv3orpCsv7C4ly8-ubDoUfrxF5xIGWmptxGWP5vi5w&r=m1RLQOGOkz9MauvVLZmiGtyWc5mA7DejbPFNE1IDj->4&m=C69wDgrjDX8_oXp1M_3bnmWOOZdGqwBBG9vzkyGDWGQ&s=oC86KD_RJ1T6rfzi3x5zFT1Ri13ELpKmsyFqpgDbgFg&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?
