Re: must-fix list for 2.6.0

Robert Love
2003-04-30T23:41:03Z

On Wed, 2003-04-30 at 19:21, Andrew Morton wrote:

> A few kernels ago, OpenOffice would take sixty seconds to just flop down a
> menu if there was a kernel build happening at the same time. That is just
> utterly broken, so if we're going to leave the sched.c code as-is then we
> *require* that all applications be updated to not spin on sched_yield.

Just as a note (I know its not an excuse), Red Hat 9 has Open Office
with the dumb sched_yield() calls removed. It runs quite nice.

> Has anyone looked at what Andrea did in -aa? I assume some suitable
> compromise was achieved there.

Well, his base O(1) scheduler does not have 2.5's sched_yield()... but
he has a patch (I guess that he wrote) on top which changes the
semantics a bit. It looks like he drops the task one priority level
each call, but if it is ever to-be-moved to a queue all by its lonesome,
the task is put on the expired array instead.

Also, he has a check at the start that, if it is in a queue all by
itself (even before it is moved) the call just returns.

Not sure what all these changes add up to...

Robert Love