parallel compilation fails

parallel compilation fails

[Wayne Davison]

Since I'm a big fan of distcc these days, it saddens me that my favorite
shell fails to compile using parallel compilation (and thus, cannot
benefit from distcc) -- i.e. "make -j3" fails in the module-build rules
when some temp-file names get used at the same time in parallel threads.

There was some email back in 1996 on this subject, such as this one from
Zefram:

    http://www.zsh.org/mla/workers//1996/msg01930.html

Is this something that we think we can fix?  It looks like some of the
features from this old patch are there, and some are not.  Trying to
wrap my head around the module-make setup is hurting my brain, and I'd
rather avoid it if someone else is already familiar with what's going on
and can fix it easily.  If it's not fixable, what's the work-around?  To
do multiple makes?  I've done this:

    make prep       # Without this, the "make -j3 bin" fails.
    cd Src
    make -j3 bin
    make modules
    cd ..
    make -j3

This appears to work, but I don't know if it's safe or not.

..wayne..

Re: parallel compilation fails

[Peter Stephenson]

Wayne Davison wrote:
> Since I'm a big fan of distcc these days, it saddens me that my favorite
> shell fails to compile using parallel compilation (and thus, cannot
> benefit from distcc) -- i.e. "make -j3" fails in the module-build rules
> when some temp-file names get used at the same time in parallel threads.
> 
> There was some email back in 1996 on this subject, such as this one from
> Zefram:
> 
>     http://www.zsh.org/mla/workers//1996/msg01930.html
> 
> Is this something that we think we can fix?

I'm sure it's fixable, but it's unlikely it's going to be high on
anybody's priority list.  Fixing dependencies is non-trivial at the best
of times.

-- 
Peter Stephenson <pws@csr.com>                  Software Engineer
CSR Ltd., Science Park, Milton Road,
Cambridge, CB4 0WH, UK                          Tel: +44 (0)1223 692070


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