Gentoo Archives: gentoo-user

From: Jeremi Piotrowski <jeremi.piotrowski@×××××.com>
To: gentoo-user@l.g.o
Subject: Re: [gentoo-user] is multi-core really worth it?
Date: Wed, 22 Nov 2017 07:26:08
Message-Id: 20171122072601.GA18724@gentoo-tp
In Reply to: [gentoo-user] is multi-core really worth it? by Raffaele Belardi
1 On Wed, Nov 22, 2017 at 07:52:54AM +0100, Raffaele Belardi wrote:
2 > Hi,
3 >
4 > rebuilding system and world with gcc-7.2.0 on a 6-core AMD CPU I have the impression that
5 > most of the ebuilds limit parallel builds to 1, 2 or 3 threads. I'm aware it is only an
6 > impression, I did not spend the night monitoring the process, but nevertheless every time
7 > I checked the load was very low.
8
9 multi-core is definitely worth it. Any non-trivial package
10 (wine,glibc,gcc,llvm,qt off the top of my head) will spend a long time
11 building many files that can be built in parallel with multiple make jobs.
12
13 That being said: if you do a world rebuild you will have lots of packages
14 that spend ~40 seconds doing their autoconf run, only to build 2-3 sources
15 files. On an 8-core machine at work, I get good results using parallel
16 emerge jobs (emerge -jX). For your 6-core AMD CPU (assuming it actually
17 has 12 threads) I'd start with 'emerge -j3' and MAKEOPTS='-j12 -l16'.
18 That should get you a nice speedup, but may require a bit more ram.

Replies

Subject Author
Re: [gentoo-user] is multi-core really worth it? Neil Bothwick <neil@××××××××××.uk>
Re: [gentoo-user] is multi-core really worth it? David Haller <gentoo@×××××××.de>
Re: [gentoo-user] is multi-core really worth it? Raffaele Belardi <raffaele.belardi@××.com>