Re: anticipatory scheduling questions

[Andrew Morton <akpm@digeo.com>]

"Felipe Alfaro Solana" <felipe_alfaro@linuxmail.org> wrote:
>
> ----- Original Message ----- 
> From: Andrew Morton <akpm@digeo.com> 
> Date: Fri, 28 Feb 2003 11:14:18 -0800 
> To: "Felipe Alfaro Solana" <felipe_alfaro@linuxmail.org> 
> Subject: Re: anticipatory scheduling questions 
>  
> > "Felipe Alfaro Solana" <felipe_alfaro@linuxmail.org> wrote: 
> > > I have done so: Evolution is a complex application with many interdependencies and is  
> > > not very prone to launch diagnostic messages to the console. Anyways, I haven't seen  
> > > any diagnostic message in the console. I still think there is something in the AS I/O scheduler  
> > > that is not working at full read throughput. Of course I'm no expert.  
> >  
> > It certainly does appear that way.  But you observed the same runtime 
> > with the deadline scheduler.  Or was that a typo? 
> >  
> > > > 2.4.20-2.54 -> 9s   
> > > > 2.5.63-mm1 w/Deadline -> 34s   
> > > > 2.5.63-mm1 w/AS -> 33s  
>  
> It wasn't a typo... In fact, both deadline and AS give roughly the same
> timings (one second up or down). But I 
> still don't understand why 2.5 is performing so much worse than 2.4.

Me either.  It's a bug.

Does basic 2.5.63 do the same thing?  Do you have a feel for when it started
happening?

> Could a "vmstat" or "iostat" dump be interesting? 

2.4 versus 2.5 would be interesting, yes.