Why does make do a -j3 -j1?

[dmbtech]

Im not sure if this is the right forums, but here it goes.

Hey, this is my make.conf file:
CFLAGS="-march=prescott -O2 -pipe -msse3 -fomit-frame-pointer"
CHOST="i686-pc-linux-gnu"
USE="nptl nptlonly ipv6"
CXXFLAGS="${CFLAGS}"
#CXXFLAGS="-O2 -mcpu=i686 -pipe"
MAKEOPTS="-j3"

I put -j3 thinking it would improve compile time because of my dual core proc. But when I look at some builds building, like glibc, I see it putting a make -j3 -j1. Doesn't that cancel the -j3? Why is there a -j1 there? Thanks for the help.

[nixnut]

Moved from Installing Gentoo to Portage & Programming.
Better off in here I think.

[UncleOwen]

Doesn't that cancel the -j3?

Yes.

Why is there a -j1 there?

Because some builds are known to be broken with -jX for X > 1.