Speed up Emerge by compiling in RAM with tmpfs
After testing this on a couple of emerges I am quite confident it works AS LONG AS YOU HAVE ENOUGH RAM – enough is 768M or more, although may be okay on 512M with a minimal desktop or X-less server. Tested on three machines with (768M, 1G, and 3G of RAM). The emerge of xorg-server went from 1.5 hours to about 20 minutes on an athlon-xp, for example.
Portage uses /var/tmp/portage (by default) as it’s working directory, everything is built in there before it gets merged to /. So, why not stick /var/tmp/portage in RAM? It’s a tmp directory after all, saves all that I/O bottleneck…
Interested? Okay, here’s what you have to do…
(I assume you are su’d as root, if not prepend sudo to all the following commands)
| #vim /etc/fstab |
add the following line to the end -
| none /var/tmp/portage tmpfs nr_inodes=1M 0 0 |
before we mount it, you may want to clear out your on disc /var/tmp/portage -
| # rm -fdr /var/tmp/portage/* |
mount your new tmp directory -
| # mount /var/tmp/portage |
try an emerge
| # emerge freeciv |
quick wasn’t it!
notes:
1. I haven’t had more than 130M used on an emerge yet, that was on an update (emerge -u world), however, I am not sure of the upper limits of the size of this directory during big/multiple emerges. It depends on how often portage/emerge clears it out. Anybody know, and can this behaviour be changed?
2. If you want to set an exact size for this you can change the entry in your fstab to -
| none /var/tmp/portage tmpfs nr_inodes=1M,size=256M 0 0 |
I would not go below 256M for safety’s sake!!!
ADDENDUM:
creating a tmpfs seems to default to 50% of your total RAM size. Not to worry, as it doesn’t use much if it isn’t populated with files. If it fills up emerge fails with “No space left on device”! I had set size=100M and emerged mysql. mysql peaks at around 140M.
- It would be useful to know what the biggest package in portage is.(?) When emerged how much space does it use at the maximum, if we added, say, 10% to the figure then that would give us our maximum acceptable size for the tmpfs.
- Most of the space is taken up when emerge unpacks a dist tarball into /var/tmp/portage. It only seems to unpack one package at a time, and then removes it when it has finished. This behaviour may be different dependent on your setting for MAKEOPTS in make.conf, can’t confirm this as I have only tested it with “-j2″ (the default).
- There’s an entry on the WIKI that I missed that has a very cool script that turns this on and off when you need it, it’s http://gentoo-wiki.com/TIP_Speeding_up_portage_with_tmpfs
Source: http://forums.gentoo.org/viewtopic-t-541460.html
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