[PATCH 0/5] Improve make and make check parallelism

[Yury Khrustalev]

On Fri, Jun 12, 2026 at 01:34:03PM -0300, Adhemerval Zanella wrote:
> One thing that has bothered me for some time is that neither 'make' nor
> 'make check' scales well with the number of cores: although each
> subdirectory builds with full internal parallelism, the top-level
> recursion is marked .NOTPARALLEL and runs the sub-makes strictly one at
> a time.
> 
> Every subdirectory's compile tail and link step therefore leaves most
> cores idle, and the constant additions to the testsuite keep making it
> worse.  Profiling the check phase also showed that some of the tests-special
> are among the main culprits, most notably check-installed-headers, which
> performs dozens of serial compiler invocations per installed header.
> 
> This series makes the subdirectory recursion run in parallel while
> encoding the ordering the serial recursion relied on as explicit
> dependencies:
>
> ...
>

I've checked on my usual dev machine and I get 40% speed-up, this is amazing.

Thanks,
Yury