If you had a month to improve gcc build parallelization, where would you begin?

[Tom Tromey]

>>>>> "Joern" == Joern Rennecke <joern.rennecke@embecosm.com> writes:

Joern> The likelyhood that a test depends on the outcome of the last few
Joern> n tests is rather low.  So you could tests speculatively with an
Joern> incomplete set of defines, and then re-run them when you have
Joern> gathered all the results from the preceding tests to verify that
Joern> you have computed the right result.

I think there are things that can be parallelized without needing to do
any speculation.  For example, AC_CHECK_HEADERS is often invoked with
many header files.  These could in most cases be checked for in
parallel.  Similarly for AC_CHECK_FUNCS.

Beyond that you could define a general way to run checks in parallel and
then just change the gcc configure script to use it, using knowledge of
the code to decide what dependencies there are.

Whether or not this would yield a big enough benefit, though ...

I had the vague impression that this was being looked at in upstream
autoconf, but I don't actually follow it any more.

Tom