incremental linking?

[Hal Daume III]

Claus,

How did you get ghc to use gld when doing --make instead of standard
ld?  I'm having the exact same problem you were and I'd love to make it
work faster.

Thanks in advance,

 Hal

--
Hal Daume III

 "Computer science is no more about computers    | hdaume@isi.edu
  than astronomy is about telescopes." -Dijkstra | www.isi.edu/~hdaume

On Sat, 30 Nov 2002, Claus Reinke wrote:

> 
> It seems that Sun's ld was indeed the weak link. Switching to
> Gnu's ld (*) brought the linking time down to just under 1 minute,
> both on the machine that used to take 6 minutes and on the 
> older one that used to take 20 minutes!
> 
> I don't know whether Sun's lds themselves are to blame or whether 
> ghc/gcc generate output that suits Gnu's ld better than it does Sun's 
> ld, but as long as ghc remains as it is, that doesn't really make a 
> difference for our purposes. 
> 
> (slow) ld -V
> ld: Software Generation Utilities - Solaris Link Editors: 5.8-1.276
> 
> (better) ld -V
> ld: Software Generation Utilities - Solaris Link Editors: 5.9-1.344
> 
> (winner) ld -V
> GNU ld version 2.13.1
>   Supported emulations:
>    elf32_sparc
>    elf64_sparc
> 
> We haven't done extensive testing yet, and earlier versions
> of binutils (up to and including 2.13) are reported to have 
> problems on Solaris, so don't throw away Sun's tools, but it 
> looks as if our case is now closed (and incremental linking
> isn't an issue anymore with these new link times!-)
> 
> Thanks for the helpful feedback, and Good Luck with the
> other suspiciously slow systems!
> 
> Claus
> 
> (*) a little stumbling block here: gcc refers to PATH only *after* 
>   perusing its preconfigured search paths. In our case, those included 
>   /usr/ccs/bin, so we had to set GCC_EXEC_PREFIX instead (which 
>   is used before the preconfigured paths). Check with:
>   gcc -print-search-dirs
> 
> ----- Original Message ----- 
> From: "Claus Reinke" <claus.reinke@talk21.com>
> To: <glasgow-haskell-users@haskell.org>
> Sent: Friday, November 29, 2002 12:02 PM
> Subject: Re: incremental linking?
> 
> 
> > >I haven't been able to discern any pattern among those experiencing long
> > >link times so far, except that -export-dynamic flag used by the dynamic
> > >loader stuff seems to cause the linker to go off into space for a while.
> > 
> > We're still investigating here, but just a quick summary for our own
> > (large) project:
> > 
> > - nfs doesn't seem to have too drastic effects, even in-memory disks
> >   don't speed things up, time seems to be spend in computation
> > - on our (admittedly overloaded and dated) main Sun Server, linking
> >    could take some 20 minutes!
> > - we've found a more modern (and not yet well-utilized;-) Sun server,
> >   bringing the time down to 6 minutes..:-(
> > 
> > (from that, I thought linking might have to be expensive - how naive!-)
> > 
> > - the same program on my rather old 366Mhz PII notebook links in
> >    about 1 minute (I didn't notice that at first, because overall compile
> >    time is longer on my notebook - but that turns out to be caused by 
> >    a single generated file, for which the assembler almost chokes; after
> >    all, the notebook "only" has 192Mb memory, and the disk is crammed)
> > - with the laptop as reference, I'd guess the problem is not ghc's fault
> >    (unless it does things drastically different on cygwin vs solaris?)
> > - on our Suns, gcc (and hence ghc) seem to use the native linker
> > - sunsolve lists several linker patches to address problems like
> >   "linker orders of magnitude slower than Gnu's". We seem to have
> >   those patches, but we're checking again..
> > 
> > moral so far: if compilation of big projects takes a long time, it is worth
> > checking where that time is spend. for the same project, on different
> > systems, we've got different bottlenecks:
> > 
> > - large (generated) files [all systems]: assembler needs an awful lot
> >   of space (not enough space->compile takes forever)
> > - network disks: import chasing takes a lot of time
> > - Suns (?): linking takes too long
> > 
> > will report again if we get better news..
> > 
> > Claus
> > 
> > PS. if we get linking times down to what seems possible, incremental
> >        linking would no longer be urgent - we'll see..
> > 
> > 
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