Which SCHED_ for DB server

Kris Kennaway kris at obsecurity.org
Tue Sep 6 01:22:37 PDT 2005

On Tue, Sep 06, 2005 at 09:46:12AM +0200, O. Hartmann wrote:
> Kris Kennaway wrote:
> >On Thu, Sep 01, 2005 at 10:53:39AM +0200, Claus Guttesen wrote:
> > 
> >
> >>>I'm building a server that will run PostgreSQL with a database
> >>>containing several 10s of million records. The only things happening on
> >>>this box will be the SQL processes and other processes to parse raw data
> >>>and load into the DB. Users = a few connections via HTTP from an
> >>>intranet server (not more than 5 concurrently).
> >>>
> >>>I was wondering what is the best SCHED_ to set in the kernel.
> >>>I currently have SCHED_4BSD but was wondering if _ULE would be better
> >>>for this
> >>>     
> >>>
> >>For prod. use I would recommend SCHED_4BSD atm. The 4BSD-scheduler
> >>does seem to be more stable on SMP and up.
> >>   
> >>
> >
> >ULE might be OK on SMP with 6.0 and above, but performance seems to be
> >a bit lower than 4BSD in my tests.  Try it yourself and see which is
> >better.
> >
> >Kris
> > 
> >
> Interesting.
> An, by the way, what are the benefits of ULE at this moment? Is it still 
> a more experimental scheduler for the far future on SMP based machines 
> or do we have benefits in UP/SMP?

It was supposed to provide higher performance (and did for a while,
modulo panics), but at the moment it still needs work.

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