In comp.sys.super John Sasso wrote:
> I have a question about running single-CPU jobs for dedicated processing
> on a multiprocessor IBM SP2 or SP4.
>
> QUESTION: Can an application be run as dedicated and non-shared on an
> SP2 or SP4 run 100% dedicated from start-to-finished on a CPU without
> EVER being process-swapped (context-switched) by another process, in
> particular a process that runs as root (e.g., the scheduler, some
> maintenance daemons, etc.), even if the duration of the
> swap/context-switch is very small? In addition, will such a process
> have access to the CPU's ENTIRE cache so there'd never be a concern
> about another process (even a high-priority root process) using the same
> CPU's cache? (Assume the program the user runs in question is one that
> uses static arrays and does not do any file I/O or I/O to stdin/stdout).
>
> I've heard of the use of processor affinity for running programs in
> so-called dedicated, non-shared mode, but I need know know if processor
> affinity or some other mechanism on the IBM SP2 or SP4 would allow a
> user process to run absolutely 100% dedicated, without EVER being
> context-switched by ANY process or thread whatsoever, on a CPU, nor be
> interrupted by any type of system interrupt (e.g. network I/O).
>
> Any supporting docs you can provide would be great. Thanks!
>
> -john

What's an IBM SP4?

[c.p. moderator: John for a 1-line question like that, please cut the
original attribution down and not use the entire text body.]

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