On Wed, 3 Mar 2004, Stefan [iso-8859-1] Eer wrote:
> I do not understand, why 'ratio' comes out that different (92-103% vs. 137-148%)
> for 5.2.1 vs. -CURRENT (for -j4 and up, where HT plays a role).
> Is the process accounting different, or has the scheduler been changed to make
> better use of logical processors ???
ULE is better in 5.2-CURRENT than in RELENG_5_2. However, the significant
change that is contributing to this is the improvements to make(1). Prior
to 5.2-CURRENT, 'make -jX' would poll every 20ms for completed children,
and then schedule new children. Now there is a simplistic SIGCHILD handler
that allows new children to be scheduled immediately, and of course
eliminates the overhead of the polling. Since buildworld is such a large
consumer of fork/exec, it's not surprising that this change helps a lot.