On Mon, May 18, 2020 at 9:25 PM Steve Langasek <steve.langa...@ubuntu.com> wrote: > > Hi Christian, > > On Mon, May 18, 2020 at 03:57:39PM +0200, Christian Ehrhardt wrote: > > Hi, > > I was revisiting one of the packages the server team usually looks > > after: `rdma-core`. > > Late in the focal release cycle I was asked to mark the `pandoc` > > build-dependency with !i386 as it doesn't exist there and was causing > > problems [1]. I was revisiting this now to resolve it in a better way > > to be able to make the package a sync again. > > > I had a discussion with Debian and started to wonder why this is a > > problem for Ubuntu at all. That made me identify a weak spot in my > > understanding of partial i386 [3][4]. > > The odd thing to me is that `rdma-core` isn't part of the i386 > > whitelist [5], so why would it be a problem that the d/control lists > > pandoc as build-dep - I'd have expected it to not build at all. > > Then I realized that germinate still pulls it in [6], but failed to > > see why. Is it that we actually have i386 builds on the whitelist and > > in addition all-of-its-build-deps ? > > The relevant germinate output is > https://people.canonical.com/~ubuntu-archive/germinate-output/i386.groovy/i386+build-depends > > This shows the source packages that are in the set, as well as why they're > pulled in. > > rdma-core is there as a dependency of openmpi, which is a dependency of > mpi-defaults, which is a build-dependency of boost.
Thank you for this link on top of the ones I have checked. > There are a lot more packages that need to be built on i386 than those that > are directly in the whitelist, because we need a closure over > build-dependencies in order to be able to build the packages that are in the > whitelist. I was seeing that it was more, thanks for confirming that it is due to the dependencies. I have added this to the wiki page [4] so that fewer people have to ask again :-) > > Furthermore that might explain why the only dependency left is openmpi > > which also isn't part of the whitelist [5] but shown in germinate [6]. > > > $ reverse-depends --release=groovy --arch=i386 src:rdma-core > > Reverse-Depends > > * libopenmpi-dev (for libibverbs-dev) > > > I now wonder if a much easier fix might be to remove the build > > dependency to rdma-core on src:openmpi (for i386 only) which would > > finally make rdma-core really not building on i386. Is that a better > > solution? Openmpi in turn has a much longer list of things depending > > on it, doing the cut at openmpi->rdma-core seems to be the cleanest. > > I have no preference on whether we do the cut above or below rdma. If you > find that having openmpi not depend on rdma-core on i386, and keeping > rdma-core in sync, is easier for maintenance, then that's fine. Looking at openmpi more in detail it seems someone called "Steve" already gave this a shot :-) The current Delta we have there is: * Also disable the direct build-dependency on libibverbs-dev (from rdma-core) on i386. * Disable libfabric support on i386 to avoid pulling in rdma-core. So since we already have delta on openmpi due to i386 let us try to reduce it to just openmpi. It seems the build deps are correct, but there is a hard dependency statement in d/control: libibverbs-dev (>= 1.1.7) [!kfreebsd-i386 !kfreebsd-amd64 !hurd-i386] That just needs the same !i386 treatment as the build-deps you have already done. Hopefully rdma-core will no more be pulled then. I'll do the openmpi change and re-check the i386 germinate a day later if rdma-core really was let go on i386. > > But then I have realized that while there are not more runtime > > dependencies, build dependencies in i386 seem to be quite a lot still > > (reverse-depends --release=groovy --arch=i386 --build-dep > > src:rdma-core shows 41). > > As far as I know these are all false-positives; I don't know that > reverse-depends --build-dep --arch=foo ever does anything useful. > Spot-checking the output, I see that most of these packages only have arch: > all packages published on i386. > > > With this mail I'd look for: > > a) general guidance on `is the effective i386 build = whitelist + > > build-deps` > > b) feedback on the suggestion to remove the rdma-core build dep on > > openmpi; or would all 41 build-deps have to go away? > > c) other alternatives > > > The answers to (a) we could add to the wiki [4]. > > The answers to (b)+(c) will hopefully help me to go on with this, it > > might eventually come down to keeping the current Delta (trivial) in > > rdma-core, but along the way understanding the inner workings better > > would be great. > > > > [1]: https://launchpad.net/ubuntu/+source/rdma-core/28.0-1ubuntu1 > > [2]: https://github.com/linux-rdma/rdma-core/pull/756#issuecomment-630138899 > > [3]: > > https://discourse.ubuntu.com/t/community-process-for-32-bit-compatibility/12598 > > [4]: https://wiki.ubuntu.com/i386 > > [5]: > > https://git.launchpad.net/~ubuntu-core-dev/ubuntu-seeds/+git/i386/tree/i386 > > [6]: > > https://people.canonical.com/~ubuntu-archive/germinate-output/i386.focal/i386+build-depends.sources > > -- > Steve Langasek Give me a lever long enough and a Free OS > Debian Developer to set it on, and I can move the world. > Ubuntu Developer https://www.debian.org/ > slanga...@ubuntu.com vor...@debian.org -- Christian Ehrhardt Staff Engineer, Ubuntu Server Canonical Ltd -- ubuntu-devel mailing list ubuntu-devel@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-devel
