svn commit: r197652 - stable/7/sys/kern

[Matthew Fleming]

> >   sched_ule in stable/7 has a bug (introduced in r180607) where a
thread
> >   that is running often will appear to not be running much at all.
> Why is this not a problem on HEAD ?

I can't say definitively there's not a bug on HEAD of some kind, but
when I ran a CPU hog and looked at the output of top(1), on HEAD the hog
was listed as near 100%, and on stable/7 it was listed as 0% after a few
seconds for the system to settle.  Since the code looked at least
somewhat different and the bug did not reproduce on HEAD, I assumed it
was only a problem on stable/7.  I had to run HEAD code in a virtual
machine, perhaps this made a difference?

>From a code inspection standpoint, I don't see anything obvious.  On
stable/7, the set of ts_ltick in tdq_runq_rem() appears to be the reason
a cpu hog was not getting incremented by sched_tick().  On HEAD this set
is moved to sched_choose().

Thanks,
matthew