Re: [gentoo-amd64] compiling on dual-cores - only 50% usage per cpu

["Ângelo Miguel Arrifano" <miknix@gmail.com>]

On Sat, 10 Nov 2007 17:29:24 +0100
Bernhard Auzinger <e0026053@student.tuwien.ac.at> wrote:

> Hi everybody,
> 
> it's not a important question, but has anybody of you noticed when compiling 
> certain packages the load on both cpu's is only about 50%. I have the feeling 
> that it happens with packages that can not be split up into two jobs. But in 
> this case one cpu should be on 100% load and the other one at ~0%. Maybe 
> someone of you has a good explanation for this behaviour.
> 
> Rgds
> Bernhard
> -- 
> gentoo-amd64@gentoo.org mailing list
> 

I made a core metering plugin for XFCE panel some time ago.
If you use XFCE or are interested on the plugin somehow, you can get it here:

http://miknix.homelinux.com/xfce4-cpuload-plugin/

Looking to the plugin it is very visible what you say about the overall when processor
usage is 50% one of the cores is 100% and the other at 0%.
I can also state that most of single processes running on a single core, are always
migrating from one core to another maybe to distribute temperature over both cores.

The exception (at least on my hardware) is when some process is making exhaustive
I/O using interrupts. Both cores are at 0% usage but the overall cpu usage is 100%.

Also, there are packages that fails using parallel make. These packages are overriding
your MAKEOPTS="-jx" option with -j1. But, if you find that some package is overriding
the flag but builds OK with -j>1, please report on bugzilla! Specially if is a big package :) 

Best regards,
-- 
Angelo Arrifano AKA MiKNiX
CSE Student at UBI, Portugal
Gentoo Linux AMD64 Arch Tester
miknix@gmail.com
http://miknix.homelinux.com
PGP Pubkey online

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He is a man capable of turning any colour into grey.
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