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IDProjectCategoryView StatusDate SubmittedLast Update
0005796OCamlOCamlbuild (the tool)public2012-10-23 03:342012-11-19 02:40
Reporterberenger 
Assigned Togasche 
PrioritynormalSeveritymajorReproducibilityalways
StatusresolvedResolutionduplicate 
PlatformOSOS Version
Product Version4.00.0 
Target VersionFixed in Version 
Summary0005796: ocamlbuild doesn't parallelize the build
Descriptionusing -j 1 to -j 8 with a step size of 1 shows that
there is almost no parallelization of the build.
Steps To Reproduceuse option -j and make it vary up to the number of cores your machine have
TagsNo tags attached.
Attached Files

- Relationships
duplicate of 0005754assigned Not optimal parallel build of dependencies 

-  Notes
(0008295)
gasche (developer)
2012-10-23 10:14

I believe the problem you observed reflects a deeper implementation problem in the current Ocamlbuild than a simple bug. It has been on OCamlbuild's maintainers TODO list for some time, but it's not an easy problem to solve. Of course, any outside help will be warmly appreciated, ocamlbuild accepts contributions -- but I would advise working on easier issues first.
(0008298)
berenger (reporter)
2012-10-23 10:29

Instead of starting to hack into ocamlbuild, I will
start using ocp-build:

https://github.com/OCamlPro/ocp-build [^]

I guess it will parallelize the build correctly,
as does make since the 70s...

Regards,
F.
(0008302)
gasche (developer)
2012-10-23 11:09

You may also be interested in OCamlMakefile and omake

  https://bitbucket.org/mmottl/ocaml-makefile [^]
  http://omake.metaprl.org/index.html [^]
(0008315)
avsm (reporter)
2012-10-24 00:11

Which bit of OCamlbuild failed to parallelise for you? ocamlbuild discovers dependencies dynamically, so while it cannot do static scheduling as well as make, it's a lot more flexible. Some stages of the build are more serial than others, so seeing a build log helps.
(0008316)
berenger (reporter)
2012-10-24 02:31

I don't want to invest anymore of my time with ocamlbuild.
I'll just get rid of this tool from my OCaml toolchain.
(0008527)
meyer (developer)
2012-11-19 02:40

This bug has been reported (PR#5754), it's being investigated if we can shift some of the rules known in advance to be static and find more opportunities for parallel build.

- Issue History
Date Modified Username Field Change
2012-10-23 03:34 berenger New Issue
2012-10-23 10:12 gasche Relationship added duplicate of 0005754
2012-10-23 10:14 gasche Note Added: 0008295
2012-10-23 10:14 gasche Status new => resolved
2012-10-23 10:14 gasche Resolution open => duplicate
2012-10-23 10:14 gasche Assigned To => gasche
2012-10-23 10:29 berenger Note Added: 0008298
2012-10-23 11:09 gasche Note Added: 0008302
2012-10-24 00:11 avsm Note Added: 0008315
2012-10-24 02:31 berenger Note Added: 0008316
2012-11-19 02:40 meyer Note Added: 0008527


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