Comments on the KSE option

[Daniel Eischen]

On Sat, 28 Oct 2006, Matthew Dillon wrote:

>
>    (2) Just because the POSIX scheduler implements all sorts of different
>    scopes and priority schemes says NOTHING AT ALL about how programs
>    operating under such a scheduler should be apportioned cpu relative
>    to OTHER PROGRAMS WHICH ARE INDEPENDANTLY RUNNING ON THE SYSTEM.  POSIX
>    is an abstraction (or virtualization out of available resources),
>    just like everything else.  If you try to treat it as a hard requirement
>    the only result will be a broken system that might happily run everything
>    else into the ground and stop allowing root ssh logins in order to
>    accomodate a badly written POSIX program.  There are many third party
>    applications that set POSIX priorities, in particular realtime
>    priorities, that I'd rather they not actually use.  Most of these
>    programs set these priorities based on the author's attempt to tune
>    them on a single operating system (e.g. linux) and in a single operating
>    environment.
>
>    All a program can ever really do when requesting POSIX scheduling
>    resources is compete against itself.  It is the system operator, at a
>    higher level, that must control how those resources compete with
>    other programs.  That should be clear to everyone it is so obvious.

Actually, that's not quite true.  I assume you know the thing you
left out:  system scope threads compete against all the other
system scope threads in the system (from all applications, not
just within one application).

-- 
DE