Interesting analysis of linux kernel threading by IBM

[Horst von Brand]

Davide Libenzi <davidel en maticad.it>, David Lang <dlang en diginsite.com>, said:
> On Thu, 20 Jan 2000, Horst von Brand wrote:

[...]

> > Hondreds of tasks is just not a typical (perhaps even realistic)
> > workload.

> Yes it is.  
> 
> If you are running a webserver. 

Hundreds of CGIs running at the same time? Wow. But there I'd split load
among machines way before...

> Or a highly threaded application.

Higly stupid idea, typically.

> Or a machine with a lot of users.  (For example, a University unix server)

I have such machines here (dozens of users, plus random services). Rarely
gets to 10.

> Or an ftp server.  (Where is the Linux equivalent of FreeBSD's
> ftp.cdrom.com?)

Hundreds of people downloading at the same time is not the same as hundreds
of running tasks...

> It is really a question of "Where does Linux want to go?"  

Benchmarkland, or real-world useful system?

> If it wants to be a high performance server, Linux needs a new
> scheduler. 

Say which hard facts?

> If it wants to be the most efficient desktop machine, then it doesn't
> need it NOW.  However, the average number of programs people are
> running on their machine are increasing, not decreasing.  

Yes. I expert load average to be in the ones soon, not 0.1s anymore.

> Linux's real penetration has been in the server market.  Why not make
> it the best server it can be?

Nobody is saying we shouldn't do it. But before screwing around, _measure_
where the real bottlenecks (for _real_ use, not benchmarks) are.
-- 
Dr. Horst H. von Brand                       mailto:vonbrand en inf.utfsm.cl
Departamento de Informatica                     Fono: +56 32 654431
Universidad Tecnica Federico Santa Maria              +56 32 654239
Casilla 110-V, Valparaiso, Chile                Fax:  +56 32 797513

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