Re: [PATCH][plugsched 0/28] Pluggable cpu scheduler framework

[Peter Chubb]

>>>>> "Matthias" == Matthias Urlichs <smurf@xxxxxxxxxxxxxx> writes:

Matthias> Hi, Ingo Molnar wrote:
>> I believe that by compartmenting in the wrong way [*] we kill the
>> natural integration effects. We'd end up with 5 (or 20) bad generic
>> schedulers that happen to work in one precise workload only, but
>> there would not be enough push to build one good generic scheduler,
>> because the people who are now forced to care about the Linux
>> scheduler would be content about their specialized schedulers.

Matthias> I hate that. Ideally, the scheduler would be
Matthias> hotpluggable... but I can live with a reboot. I don't think
Matthias> a kernel recompile to switch schedulers makes sense, though,
Matthias> so I for one am likely not to bother. So far.

Matthias> You can't actually develop a better scheduler if people need
Matthias> to go too far out of their way to compare them.

I'd like to go further and be able to have families of schedulers that
work together  --- if you're going to vector to a scheduler anyway,
why not do it per process?  That way the special cases for SCHED_FIFO and
SCHED_RR can be moved into separate functions (likewise SCHED_ISO,
SCHED_BATCH, SCHED_GANG etc., as and when they're developed), rather
than being controlled by if() or switch() statements in a common
do-everything scheduler.

In general, it's the interactive SCHED_OTHER scheduler that's been the
problem, and the focus of most of the work.  We more-or-less know how
to do the basic POSIX schedulers.  
-- 
Dr Peter Chubb  http://www.gelato.unsw.edu.au  peterc AT gelato.unsw.edu.au
The technical we do immediately,  the political takes *forever*
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