Re: 2.6.15-rc5-rt2 slowness

Steven Rostedt
2005-12-20T14:04:19Z

On Tue, 20 Dec 2005, Ingo Molnar wrote:
>
> * Steven Rostedt <rostedt@goodmis.org> wrote:
>
> > > > Now, is the solution to bring the SLOB up to par with the SLAB, or to
> > > > make the SLAB as close to possible to the mainline (why remove NUMA?)
> > > > and keep it for PREEMPT_RT?
> > > >
> > > > Below is the port of the slab changes if anyone else would like to see
> > > > if this speeds things up for them.
> > >
> > > ok, i've added this back in - but we really need a cleaner port of SLAB
> > > ...
> > >
> >
> > Actually, how much do you want that SLOB code? For the last couple of
> > days I've been working on different approaches that can speed it up.
> > Right now I have one that takes advantage of the different caches.
> > But unfortunately, I'm dealing with a bad pointer some where that
> > keeps making it bug. Argh!
>
> well, the SLOB is mainly about being simple and small. So as long as
> those speedups are SMP-only, they ought to be fine. The problems are
> mainly SMP related, correct?

Actually, no. My test is to do a make install over NFS of a kernel that
has already been built.

The times I'm getting for the SLAB is ~26 seconds, the time for the SLOB
is 1 minute 32 seconds. So your looking at >300% slowness here. The test
bed is a UP. (I do that first before looking into SMP).

I'm still trying to keep the SLOB simple. It's the lack of sleep that is
making it hard ;)

-- Steve