Re: Heads up: Problems with parallel make

[Marco Atzeri <marco.atzeri@gmail.com>]

On 27.02.2023 23:45, Ken Brown via Cygwin-apps wrote:
> On 2/27/2023 4:41 PM, Brian Inglis via Cygwin-apps wrote:
>> Looks like the 4.4.1 release disables FIFO on Hurd and Cygwin.
>> Will be interesting to see if it is based on config test, for clues to 
>> what it does not like, or just system?
> 
> In the case of HURD, it's because of failing tests in the test suite. In 
> the case of Cygwin, it's because of the problem I reported, in which 
> parallel make using a FIFO sometimes hangs when building TeX Live.
> 
> Anyone who wants to test this with their own builds can build make with
> 
>    CPPFLAGS=-DJOBSERVER_USE_FIFO=1
> 
> That will re-enable the use a FIFO for the jobserver.  One can then 
> force make to use a pipe on a given project by using the make option
> 
>    --jobserver-style=pipe
> 
> I plan to do this myself, since I hope to debug the FIFO problem the 
> next time I see it.  It's not easy to catch, because it doesn't happen 
> with every build of TeX Live.  And when it does happen, the build has 
> typically been going on for close to two hours before it hangs.
> but it could be 
> P.S. Marco, I don't know how much trouble you want to go to on this, but 
> when you release make-4.4.1, you might also make a test release with 
> CPPFLAGS set as above.  That would make it easier for adventurous people 
> to try builds that use a FIFO.

uploaded 2 versions

4.4.1-1 default is built with CPPFLAGS=-DJOBSERVER_USE_FIFO=1
so it should behave like 4.4-1 previous build

4.4.1-2 test is vanilla build, so it should be built with pipe

the build logs are not very clear, so I need to dig more on them.

 From my tests building qpdf, both are paralleling and maybe the
-2 is slight faster, but it could be due on machine load


real    19m38.493s
user    106m36.519s
sys     7m58.323s

real    18m51.680s
user    105m14.277s
sys     7m12.061s


Regards
Marco