[gentoo-user] The effect of USE=multicall

[Stroller]

This post is not a question or a request for help - I hope you find it interesting or informative.

Whilst building wireless-tools today, I noticed for the first time the multicall USE flag.

`euses multicall` says:

   net-misc/dropbear:multicall - Build all the programs as one little binary (to save space)
   net-wireless/wireless-tools:multicall - Build the most commonly used tools as one binary

I thought I'd see whether this was generally a worthwhile and efficient USE flag to choose, so I had a google. 

Flameyes has written a blog post on the subject - it doesn't answer that question, but you may like to read it:
http://blog.flameeyes.eu/2009/10/multicall-binaries

So I decided to try this package for myself, with and without, the USE flag set:

# for foo in iwconfig iwlist iwpriv iwgetid ; do bar=`which "$foo"` ; ls -lgh "$bar" ; done                                                            
-rwxr-xr-x 1 root 82K Feb 14 04:23 /sbin/iwconfig
lrwxrwxrwx 1 root 8 Feb 14 04:23 /sbin/iwlist -> iwconfig
lrwxrwxrwx 1 root 8 Feb 14 04:23 /sbin/iwpriv -> iwconfig
lrwxrwxrwx 1 root 8 Feb 14 04:23 /sbin/iwgetid -> iwconfig
#
# for foo in iwconfig iwlist iwpriv iwgetid ; do bar=`which "$foo"` ; ls -lgh "$bar" ; done
-rwxr-xr-x 1 root 26K Feb 14 04:28 /sbin/iwconfig
-rwxr-xr-x 1 root 30K Feb 14 04:28 /sbin/iwlist
-rwxr-xr-x 1 root 14K Feb 14 04:28 /sbin/iwpriv
-rwxr-xr-x 1 root 9.5K Feb 14 04:28 /sbin/iwgetid
#

The above is from my PPC, I've checked on x86_64 and the results are similar - it makes little difference, although on x86_64 I found the individual binaries a little larger (92K) than the multicall one (83K).

AMD Athlon(tm) II Neo K325 Dual-Core Processor
CFLAGS="-march=native -O2 -pipe -fomit-frame-pointer"

eMac G4 PPC 1ghz
CFLAGS="-O2 -mcpu=powerpc -mtune=powerpc -fno-strict-aliasing -pipe"

I hope you find this information helpful, and it saves you the effort of messing around with multicall yourself.

I don't wish to make an authoritative statement but I don't think this USE flag is useful enough, in the general case, to bother messing with. I'm sure it may be useful on embedded systems.

Stroller.