[PATCH] for SCHED_ULE & libpthread issue (was Re: I like SCHED_4BSD)

Arjan van Leeuwen avleeuwen at piwebs.com
Tue Mar 16 13:54:02 PST 2004


On Monday 15 March 2004 18:17, Brian F. Feldman wrote:
> Peter Schultz <pmes at bis.midco.net> wrote:
> > Taku YAMAMOTO wrote:
> > > Unfortunately, due to over-optimization in sched_switch(), SCHED_ULE
> > > doesn't give reasonable CPU time to the threads which are using
> > > scheduler activation.
> > >
> > > Detailed analisis is described in my previous message posted to
> > > current@: "SCHED_ULE sometimes puts P_SA processes into ksq_next
> > > unnecessarily" <20040213063139.71298ea9.taku at cent.saitama-u.ac.jp>
> > >  or
> > > 	http://docs.freebsd.org/cgi/mid.cgi?20040213063139.71298ea9.taku
> > > , which didn't get broader audience :(
> > >
> > > Until the problem is fully addressed, I will propose following patch
> > > to be applied. (the least intrusive one attached in the former message)
> >
> > This patch improves interactivity under heavy load very much.
>
> My system is VERY well-behaved using this change.  (It's 2xSMP).

Here too on an SMP system. This is purely subjective though - I haven't done 
any actual benchmarking. Any chance of this patch getting in the tree?

Arjan
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