Multithread compilation doesn't use multicore on 14.1 and -current on multilib.

nolretou · 01-05-2015, 08:27 AM

Hi,

On a pure 64 bit I've compiled e.g. webkitgtk with a modified SlackBuild, using make -j4.
All cores were at 100% usage.

Now on multilib, only one core is used. The only way to make it work is to be root using "su". "su -" is unable to use all cores.

I've already noticed that with other packages, on both 14.1 and -current on three different machines.

I strictly followed the multilib installation procedure.

moisespedro · 01-05-2015, 09:08 AM

From what I remember webkitgtk can't be compiled with parallel processes.

ReaperX7 · 01-05-2015, 05:47 PM

Certain packages will only build with a single process, but multithreading must actually be coded into the software to utilize it. The 32-bit packages would have to actually be built with support for SMP. Because most 32-bit packages are not built with SMP in mind since several 32-bit CPUs do not support multithreading and SMP, these features are disabled when using 32-bit software.

thirdm · 01-05-2015, 08:10 PM

These explanations don't account for it working with plain su but not with su -. Are you passing the -j 4 on the command line or using an environment variable (MAKEFLAGS?) to pass it down? How is su being invoked? Do you first su to a root prompt and then type make or are you passing make as an argument to su?

There's also something in the man page about - needing to be the last option to su . What if you use (the recommended) -l instead of -?

Linux.tar.gz · 01-10-2015, 01:01 PM

I have the same exact problem.
When compiling a kernel on a multilib system, I'm forced to use su instead of su - or su -l if I want to see all my cpus going 100%.

Richard Cranium · 01-10-2015, 04:26 PM

Quote:

Originally Posted by nolretou

Hi,

On a pure 64 bit I've compiled e.g. webkitgtk with a modified SlackBuild, using make -j4.
All cores were at 100% usage.

Now on multilib, only one core is used. The only way to make it work is to be root using "su". "su -" is unable to use all cores.

I've already noticed that with other packages, on both 14.1 and -current on three different machines.

I strictly followed the multilib installation procedure.

What happens when you login as root and run a build?

schmatzler · 01-10-2015, 04:45 PM

Quote:

Originally Posted by moisespedro

From what I remember webkitgtk can't be compiled with parallel processes.

It can on -current.

Quote:

Sun Jun 1 19:48:54 UTC 2014
[...]
d/make-3.82-x86_64-5.txz: Rebuilt.
Patched to fix a bug with parallel builds.

Ook · 01-12-2015, 03:41 PM

Quote:

Originally Posted by Linux.tar.gz

I have the same exact problem.
When compiling a kernel on a multilib system, I'm forced to use su instead of su - or su -l if I want to see all my cpus going 100%.

I have a fairly clean install of Slackware 14.1 64 bit with multilib. Just last week I upgraded to the 3.18.2 kernel, and when I did make -j8, all 8 cores were maxed out. I used 'su -', not just 'su', and it worked fine.

Slackware 14.1 64 bit, recently updated via slackpkg
16GB ram
Amd FX 8 core 4GHz cpu

JackHair · 01-12-2015, 11:24 PM

I'm on -current multilib too and can confirm I get 100% across all cores. I do use sudo instead of su though.