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IDProjectCategoryView StatusDate SubmittedLast Update
0004935OCamlOCamlbuild (the tool)public2009-12-08 17:232013-07-12 18:15
Reporterletouzey 
Assigned Toxclerc 
PrioritynormalSeverityfeatureReproducibilityalways
StatusassignedResolutionopen 
PlatformOSOS Version
Product Version3.11.1 
Target Version4.01.1+devFixed in Version 
Summary0004935: ocamlbuild -j does not compile in parallel a parallelizable development
DescriptionI'm trying to compile Coq via ocamlbuild (See also bug 0004934). Currently, the use of the -j option brings almost no time gain on a multi-core machine (while make -j is close to 2x gain on dual-core and 3.5x gain on quad-core).

Here again, I may well be the culprit and not have written my myocamlbuild.ml in an appropriate manner. Any hint is welcome...

Best regards,
Pierre Letouzey


Instructions to reproduce:

0) you'll need camlp5 installed
1) get a copy of coq development archive
   svn checkout svn://scm.gforge.inria.fr/svn/coq/trunk/ [^] [^]
2) ./configure -local -opt
3) Launch a first build (./build is a wrapper for ocamlbuild, with no -j) :
   ./build
4) Redo the same with -j 0 :
   rm -rf _build
   ocamlbuild -j 0 coq.otarget

Here, on a quad-core machine, first build says:
Finished, 2716 targets (0 cached) in 00:13:10.

While the second one says
Finished, 2716 targets (0 cached) in 00:12:37.

On the same machine, make -j perform the same build in about 4min.
TagsNo tags attached.
Attached Files

- Relationships
related to 0005138assignedxclerc option "-j" doesn't parallelize processes on windows 

-  Notes
There are no notes attached to this issue.

- Issue History
Date Modified Username Field Change
2009-12-08 17:23 letouzey New Issue
2010-01-08 13:34 doligez Status new => confirmed
2010-01-08 13:34 doligez Description Updated
2011-06-06 13:00 xclerc Relationship added related to 0005138
2011-06-06 13:08 xclerc Status confirmed => assigned
2011-06-06 13:08 xclerc Assigned To => xclerc
2012-02-02 15:17 protz Category OCamlbuild => OCamlbuild (the tool)
2012-07-06 16:31 doligez Target Version => 4.01.0+dev
2012-07-31 13:36 doligez Target Version 4.01.0+dev => 4.00.1+dev
2012-09-07 12:53 frisch Target Version 4.00.1+dev => 4.00.2+dev
2013-06-16 18:33 gasche Target Version 4.00.2+dev => 4.02.0+dev
2013-06-16 21:25 gasche Severity major => minor
2013-06-16 21:26 gasche Severity minor => feature
2013-07-12 18:15 doligez Target Version 4.02.0+dev => 4.01.1+dev


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