FastSort Manual

Sorting in Parallel
FastSort Manual—429834-003
6-7
Selecting Processors to Run Subsort Processes
If you use commands to configure the parallel sort run, you can specify the parameters
for each subsort process in a SUBSORT command. Some parameters of the RUN
command also affect the configuration of subsort processes, as explained under
Configuring a Distributor-Collector Process on page 6-10.
If you use procedure calls to configure the parallel sort run, you can specify processors
in a call to the SORTBUILDPARM procedure and the other parameters for subsort
processes in a call to the SORTMERGESTART procedure. Other parameters of
SORTMERGESTART also affect the configuration of subsort processes, as explained
under Configuring a Distributor-Collector Process on page 6-10.
Selecting Processors to Run Subsort Processes
When you name a scratch file for a subsort process, FastSort runs the process in the
same processor that runs the primary disk process for the scratch file. If you see a
bottleneck in a processor that is running a subsort process, however, you can specify a
different processor for that process.
If a subsort process cannot run in the default processor, FastSort selects another one
from a group of processors. You can specify which processors are in the group and
which ones are not. When you specify a particular processor to run a subsort process
and that processor is not available, FastSort does not select another processor but
returns an error message.
You can specify a particular processor for a subsort process using one of the following
methods, depending on whether you use commands or procedures:

The CPU parameter of the SUBSORT command

The process-start parameter of the SORTMERGESTART procedure

The CPU attribute of a SUBSORT DEFINE
You can specify a group of processors for FastSort to select from by using any of the
following:

The CPUS and NOTCPUS commands (you can specify either or both commands)

The cpu-mask and not-cpu-mask parameters of the SORTBUILDPARM
procedure (you can specify either or both parameters)

The CPUS and NOTCPUS attributes of a SORT DEFINE (you can specify either or
both attributes)