Re: /proc/cpuinfo format - arch dependent!

[Paul Jackson <pj@sgi.com>]

Jim wrote:
> I see two problems with encouraging applications to get involved
> with processor selection.

I suspect you are confusing "application" with "not kernel".

There are basically three layers of software on big systems:

 1) kernel
 2) administration (system services, libraries and utilities)
 3) application

Something like a batch manager is an example in layer (2) that needs
extensive knowledge of a systems hardware, and extensive ability to
manage exactly what runs and allocates where.

Large systems very much expect to manage what threads run where. These
API's are already present - check out sched_setaffinity, mbind,
set_mempolicy, and cpusets.  The details of what hardware is where,
including memory, processor and interconnect, are also there as well, in
various /proc and /sys files.

No - we don't expect the application to know all this.  But we absolutely
require that various admin level programs know this stuff in intimate
detail, and enable the administration of large systems in a variety of
ways.

-- 
                  I won't rest till it's the best ...
                  Programmer, Linux Scalability
                  Paul Jackson <pj@engr.sgi.com> 1.650.933.1373, 1.925.600.0401
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