> On Oct. 14, 2014, 9:06 p.m., Timothy St. Clair wrote: > > configure.ac, line 281 > > <https://reviews.apache.org/r/26426/diff/1/?file=714874#file714874line281> > > > > Is there a reason you want to leave debug symbols out of optimized > > builds? > > > > cmake has the pattern correct imho: > > Release > > Debug > > ReleaseWithDebug > > > > A ReleaseWithDebug allows packagers, such as myself, to build > > w/debugsymbols that are stripped out into a .debuginfo package which can be > > used by developers for tracing "When bears attack". Granted that it is > > tenuous debugging at best, but it's better then nothing. > > > > So I think we want all three modes, stripping all debug information is > > not really idea. > > Cody Maloney wrote: > My main motivation is to shrink the size of libmesos. Yesterday sugis in > #mesos had one which was 213M. For the buildbot internally, full debian > packages (which are compressed) of mesos weign in at 165M a piece (Yes, > stripping post-build would help a lot, but why build it to begin with?). Most > of this is debug info. Also, we build a bunch of different ways, and when > libmesos is as big as it is, a decent amount of time ends up being spent on > disk I/O reading / writing all the debug info when we are really just trying > to ensure it builds on all the different platforms (Not to mention storage > and file size shipping things around the network to centralized repositories). > > The simple toggle between debug and release, removing the legacy logic > gets us most of the benefit. > > If you have a good place to point me for what is needed to get a > 'ReleaseWithDebug' info build up and running I can definitely work on adding > that as well. > > Cody Maloney wrote: > It is also entirely possible to specify custom CXXFLAGS + CFLAGS with > this patch to get the old "optimized debug" build. The flags set by > --enable-debug (or not having it), to get back the "optimized debug" build > from before. > > Timothy St. Clair wrote: > I suppose rpm builds default CXXFLAGS to '-O2 -g ...', so I can buy the > argument of just making it easier on the average person.
Re-opening because conflating debug and optimization under a single flag seems a bit confusing to me. In practice, we run mesos **with optimizations** (for free performance win), and **with debugging symbols** (for meaningful backtraces and core dumps), which was previously the default but now requires the setting of CXXFLAGS to obtain. :( For development, I think by default we need debugging symbols turned on. Otherwise most people will forget to configure with `--enable-debug` and consequently will need to recompile everything when they encounter a backtrace or need to debug. CI jobs will encounter this issue as well. If there are use cases that merit no debugging symbols, seems nice to make that explicit given it runs the risk of making debugging difficult. Thoughts? - Ben ----------------------------------------------------------- This is an automatically generated e-mail. To reply, visit: https://reviews.apache.org/r/26426/#review56573 ----------------------------------------------------------- On Oct. 14, 2014, 11:07 p.m., Cody Maloney wrote: > > ----------------------------------------------------------- > This is an automatically generated e-mail. To reply, visit: > https://reviews.apache.org/r/26426/ > ----------------------------------------------------------- > > (Updated Oct. 14, 2014, 11:07 p.m.) > > > Review request for mesos, Benjamin Hindman and Timothy St. Clair. > > > Repository: mesos-git > > > Description > ------- > > Reworks building mesos in "debug" vs. "release". By default, mesos is now > built in release (no debug info, optimized build). If '--enable-debug' is > specified to configure, than optimization will be turned off, and debug info > will be turned on. > > This also adds a variable 'DEBUG' to the build environment, which people can > use in code to see if mesos is built with debugging to enable extra > assertions / checks. For release builds we may want to set 'NDEBUG' which > removes assert()'s, but that is a seperate discussion. > > Main benefits: > 1) Getting a build to include/exclude debug information at will is feasible. > Before some things like using clang would forcibly enable debug info in all > cases > 2) libmesos.so and the other binaries which get packaged up for use in > distributions shrink considerably without manually stripping post-build > (Improves build time, makes packaging cleaner) > > > Diffs > ----- > > configure.ac 2b372e06006250b5230956ef096473e98f3fa590 > > Diff: https://reviews.apache.org/r/26426/diff/ > > > Testing > ------- > > Built with both --enable-debug and without, checking that the flags get > passed through correctly. > > > Thanks, > > Cody Maloney > >
