comments on the patch for a .SERIAL target (https://savannah.gnu.org/patch/?5108)

[Grothausmann, Roman Dr.]

Dear mailing list members,


Basically I just want to post a comment on the patch for a .SERIAL target 
(https://savannah.gnu.org/patch/?5108) that I've applied the proposed patch to 
make's git-repo for the releases 3.81, 3.82, 4.0 and 4.1:
https://github.com/romangrothausmann/make/branches
It seems to work as expected but savannah tells me: "You are not allowed to post 
comments on this tracker with your current authentification level."

I've up-voted this contribution because it seems to be the essential solution to 
often reoccurring problems I have when (mis-) using GNU-Make for 
image-processing. In contrast to make's common use to compile source-code I use 
make to run CLIs for 3D image processing (see e.g. 
https://github.com/romangrothausmann/ITK-CLIs). For tomographic datasets of 
about 10GB some sophisticated commands need more than 50% of our 256GB of RAM so 
that multiple such jobs lead to thrashing during swapping or get killed by the 
kernel's OOM-killer. However, many other jobs do not need so much memory and can 
perfectly run in parallel which for our 24 CPUs gives a significant reduction in 
total processing time.
As pointed out on https://savannah.gnu.org/bugs/?42288 an option to limit 
started jobs by current mem usage is very tricky (which I understand) so Cesar 
Crusius' contribution to "manually" mark some rules to not run in parallel would 
be a great feature.
A possible improvement to that feature would be to even work for dependencies 
that get created by make from Makefiles in subdirectories. Currently, I only get 
the intended behaviour by coping and adjusting the .SERIAL target line from the 
Makefile in the sub-dir to the Makefile of the main-dir

Regards,
Roman


--
Dr. Roman Grothausmann

Tomographie und Digitale Bildverarbeitung
Tomography and Digital Image Analysis

Institut für Funktionelle und Angewandte Anatomie, OE 4120
Medizinische Hochschule Hannover
Carl-Neuberg-Str. 1
D-30625 Hannover

Tel. +49 511 532-2900