On Mon, Nov 13, 2017 at 5:29 PM, kefu chai <tchaikov@xxxxxxxxx> wrote: > On Sat, Nov 11, 2017 at 1:47 AM, Sage Weil <sweil@xxxxxxxxxx> wrote: >> We noticed a big performance regression when switching some code to >> use list::size() because although C++11 promizes that it is O(1), some of >> the libstdc++'s out there are still O(n). This PR aims to fix that >> >> https://github.com/ceph/ceph/pull/18863 >> >> by adding the various devtoolset packages as dependencies to pull in >> updated build toolchains. For el7 that's devtoolset-7-{binutils,gcc-c++}. >> when running the binaries built using GCC 5.1 in an env where an old libstdc++ (typically comes with GCC 4.8): $ rados rados: relocation error: /usr/lib/ceph/libceph-common.so.0: symbol _ZTINSt8ios_base7failureB5cxx11E, version GLIBCXX_3.4.21 not defined in file libstdc++.so.6 with link time reference because libstdc++ introduced a new ABI which is incompatible with the old one. see https://gcc.gnu.org/onlinedocs/libstdc++/manual/using_dual_abi.html and https://developers.redhat.com/blog/2015/02/05/gcc5-and-the-c11-abi/ . in other words, we need to either 1) link statically with libstdc++.so or 2) include it in librados2 on distros with GCC version less than 5.1. because ceph-osd (and other daemons packages) => ceph-base => ceph-common => python-rados => librados2. i think the 2) approach is better. what do you think? >> I'm not sure what the requirement for deb-based distros is. >> ubuntu-toolchain-r? > > for ubuntu trusty, yes. for old stable (jessie) of debian, not sure if > "apt-get -t experimental" works or not. > >> >> My preference would to move our build requirements forward so that you >> have to have a modern libstdc++ in order to build, allowing us to make >> C++11-ish assumptions (like an O(1) list::size()). >> >> 1) Is this needed for xenial, or just trusty? > > it's just trusty. xenial comes with gcc 5.3.1, see > https://packages.ubuntu.com/search?keywords=gcc&searchon=names&suite=xenial§ion=all. > >> >> 2) If only trusty, should we do something weird here to keep >> buliding for it post-luminous, or can we (finally!) drop the trusty >> builds? > > i'd vote for dropping it. but if we need to stick with trusty, here > comes the weird thing: https://github.com/ceph/ceph-build/pull/914 =) > >> >> sage >> -- >> To unsubscribe from this list: send the line "unsubscribe ceph-devel" in >> the body of a message to majordomo@xxxxxxxxxxxxxxx >> More majordomo info at http://vger.kernel.org/majordomo-info.html > > > > -- > Regards > Kefu Chai -- Regards Kefu Chai -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
