Bug 164484 – autotools builds does not take profits of all CPU power (even with dual core)

• Product: Portage Development
• Status: RESOLVED WORKSFORME

[Description David Carlos Manuelda 2007-01-30 00:22:21 UTC]

When you emerge something wich is a library and needs to be built with libtool utility, you miss half of the complete CPU power and thus it takes more to compile than other C++ program (not library).

I noted this when re-emerging for example xine-lib (or kdelibs...) and I saw that my 2 processors (I have an amd64 X-2) are at 50%, while in other emerges, they are at 100% both. I have makeopts="-j3" but it seems that libtool ignores this, or set makeopts="-j1" instead.

Reproducible: Always

Steps to Reproduce:
1.have multiple CPU (for example a dual core X-2) and a CPU monitor (ie superkaramba wit a theme)
2.emerge some library
3.see that two processors are at 50% instead of near 100%



Expected Results:  
To compile at full speed as all other non-libs programs do.

[Comment 1 Zac Medico 2007-01-30 01:34:54 UTC]

Such parallelization is entirely the responsibility of the ebuilds src_compile() function.  Portage has no control over it.

[Comment 2 David Carlos Manuelda 2008-03-28 16:29:07 UTC]

I reopen this bug as I found a little workarround for this which works for all compilations with autotools  (and thus, I changed too the caption of the bug).

I tried raising the MAKEOPTS variable to test if it improves the compilations with autotools, and it indeed improves it.

So I suggest handling this in portage (for example the autotools eclass, or something else) to raise in two units the number of parallel compilations.

For a example, is one has MAKEOPTS="-j3", it can be set temporarily to -j4 or -j5 if autotools is being used to make current package, and revert to normal when finishing.

What do you think about this little issue?

[Comment 3 Marius Mauch (RETIRED) 2008-03-28 17:31:11 UTC]

I think people should look into using the -l option for MAKEOPTS instead of trying to figure out the right value for -j.
Anyway I don't see how portage is involved here.