We should merge this fix to the 7.10 branch. On Jan 8, 2015 11:52 PM, "Peter Wortmann" <sc...@leeds.ac.uk> wrote:
> > (sorry for late answer) > > Yes, that's pretty much what this would boil down to. The patch is trivial: > > https://github.com/scpmw/ghc/commit/29acc#diff-1 > > I think this is a good idea anyways. We can always re-introduce the data > for higher -g<n> levels. > > Greetings, > Peter > > > On 05/01/2015 00:59, Johan Tibell wrote: > >> What about keeping exactly what -g1 keeps for gcc (i.e. functions, >> external variables, and line number tables)? >> >> On Sun, Jan 4, 2015 at 5:48 PM, Peter Wortmann <sc...@leeds.ac.uk >> <mailto:sc...@leeds.ac.uk>> wrote: >> >> >> >> Okay, I ran a little experiment - here's the size of the debug >> sections that Fission would keep (for base library): >> >> .debug_abbrev: 8932 - 0.06% >> .debug_line: 374134 - 2.6% >> .debug_frame: 671200 - 4.5% >> >> Not that much. On the other hand, .debug_info is a significant >> contributor: >> >> .debug_info(full): 4527391 - 30% >> >> Here's what this contains: All procs get a corresponding DWARF >> entry, and we declare all Cmm blocks as "lexical blocks". The latter >> isn't actually required right now - to my knowledge, GDB simply >> ignores it, while LLDB shows it as "inlined" routines. In either >> case, it just shows yet more GHC-generated names, so it's really >> only useful for profiling tools that know Cmm block names. >> >> So here's what we get if we strip out block information: >> >> .debug_info(!block): 1688410 - 11% >> >> This eliminates a good chunk of information, and might therefore be >> a good idea for "-g1" at minimum. If we want this as default for >> 7.10, this would make the total overhead about 18%. Acceptable? I >> can supply a patch if needed. >> >> Just for comparison - for Fission we'd strip proc records as well, >> which would cause even more extreme savings: >> >> .debug_info(!proc): 36081 - 0.2% >> >> At this point the overhead would be just about 7% - but without >> doing Fission properly this would most certainly affect debuggers. >> >> Greetings, >> Peter >> >> On 03/01/2015 21:22, Johan Tibell wrote: >> > How much debug info (as a percentage) do we currently generate? >> Could we just keep it in there in the release? >> >> _________________________________________________ >> ghc-devs mailing list >> ghc-devs@haskell.org <mailto:ghc-devs@haskell.org> >> http://www.haskell.org/__mailman/listinfo/ghc-devs >> <http://www.haskell.org/mailman/listinfo/ghc-devs> >> >> >> >> >> _______________________________________________ >> ghc-devs mailing list >> ghc-devs@haskell.org >> http://www.haskell.org/mailman/listinfo/ghc-devs >> >> > _______________________________________________ > ghc-devs mailing list > ghc-devs@haskell.org > http://www.haskell.org/mailman/listinfo/ghc-devs >
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