Subsystem Control Point (SCP) Management Programming Manual

Tr ac ing
Subsystem Control Point (SCP) Management Programming Manual—520619-001
B-3
The Tracing Environment
The Tracing Environment
A tracing environment consists of the trace procedure called by the tracing process, the
extended data segment to which the trace data is written, a disk file for recording the
trace records, and a collector process that copies trace data from the extended data
segment into the disk file. Two tracing environments, based on different trace
procedures and collector processes, are available:
A subsystem includes ZCOM-TKN-GETVSN-TRACE-SUPP in its supplemental
GETVERSION response to specify which tracing environment it uses. (See TRACE
Command Processing on page B-3.) The CMPTRACE environment is used by
subsystems that are configured as logical devices (LDEVs) in the system configuration
file. Only old SCP processes initiate CMP traces.
The collector process object file must reside in the same subvolume as the SCP process
object file.
SCP processes always start collector processes at low PINs.
Tracing an SCP Process
In addition to performing tracing-related activities for other subsystems, SCP processes
can trace their own activity. SCP processes use the SCPTRACE environment. See
TRACE Command
on page 5-35.
TRACE Command Processing
Management applications (including SCF) send TRACE commands to an SCP process.
The commands contain the trace information structure ZTRC-DDL-TRACE-MODIF
and one or more ZTRC-TKN-OPT tokens. The SCP process prepares a tracing
environment based on the value that the subsystem returns in the GETVERSION
response token ZCOM-TKN-GETVSN-TRACE-SUPP. The SCP process interprets the
value of ZCOM-TKN-GETVSN-TRACE-SUPP as:
Tracing Environment Trace Procedure Collector Process
SCPTRACE SCPTRACE
SCPTRACEX
DSM_TRACE_
SCPTC (old)
SCPTCOL
CMPTRACE CMPTRACE CMPTC (supported by old SCP processes
only)
Note. A D-series or G-series SCP process cannot initiate a CMP trace.