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++}. > > 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 -- 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
