On Mon, Mar 27, 2017 at 03:25:04AM -0700, Mark Millard wrote: > On 2017-Mar-27, at 2:41 AM, Dimitry Andric <d...@freebsd.org> wrote: > > > On 26 Mar 2017, at 23:36, Mark Millard <mar...@dsl-only.net> wrote: > >> > >> I upgraded from llvm40 r4 to final. An interesting result was > >> its creation of a backup package for llvm40-4.0.0.r4: > >> > >> about 13 cpu-core-hours running pkg create > >> > >> (Remember: I've been building with WITH_DEBUG= ) Its > >> single-threaded status stands out via elapsed time > >> approximately matching. > >> > >> I'll note that it was somewhat under 6 elapsed hours for > >> staging to have been populated (-j4 with 4 cores present > >> helps for this part). > >> > >> (Of course these elapsed-time figures are rather system > >> dependent, although the ratio might be more stable.) > >> > >> > >> > >> Also interesting was: > >> > >> Installed packages to be REMOVED: > >> llvm40-4.0.0.r4 > >> > >> Number of packages to be removed: 1 > >> > >> The operation will free 49 GiB. > > > > Yes, this is big. But there is no real need to build the llvm ports > > with debug information, unless you want to hack on llvm itself. And > > in that case, you are better served by a Subversion checkout or Git > > clone from upstream instead. > > > > -Dimitry > > FYI: > > Historically unless something extreme like this ends up > involved I build everything using WITH_DEBUG= or explicit > -g's in order to have better information on any failure. > > This is extreme enough that next time I synchronize > /usr/ports and it has a devel/llvm40 update I'll > likely rebuild devel/llvm40 without using WITH_DEBUG= . > I'm more concerned with the time it takes than with > the file system space involved.
In the case of LLVM, enabling debug builds does a LOT more than adding symbols. It's much more like enabling WITNESS and INVARIANTS in your kernel, except that the performance of the resulting binary is much worse than a WITNESS kernel (more like 10x slowdown). As Dimitry points out, these builds are of questionable value in ports so garbage collecting the knob might be the sensable thing to do. -- Brooks
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