Technical data

SDA Description
4 SDA Context
When invoked to analyze either a crash dump or a running system, SDA
establishes a default context from which it interprets certain commands.
When the subject of analysis is a uniprocessor system, SDA’s context is solely
process context. That is, SDA can interpret its process-specific commands
in the context of either the process current on the uniprocessor or some other
process in some other scheduling state.
When you initially invoke SDA to analyze a crash dump, its process context
defaults to that of the process that was current at the time of the crash. When
you invoke SDA to analyze a running system, its process context defaults to that
of the current process; that is, the one executing SDA.
You can change SDA’s process context by issuing any of the following commands:
SET PROCESS/INDEX=nn
SET PROCESS name
SHOW PROCESS/INDEX=nn
5 CPU Context
In a uniprocessor system only one CPU exists, and the concept of SDA CPU
context is not an issue. However, for a multiprocessor system with more than
one active CPU, SDA must maintain an idea of CPU context to provide a
way of displaying information bound to a specific CPU, such as the reason for
the bugcheck exception, the currently executing process, the current IPL, the
contents of CPU registers, and any owned spin locks. When you first invoke SDA
to analyze a crash dump, the ‘‘SDA current CPU’’ is the CPU that induced the
system failure.
Changing the CPU Context
You can use several SDA commands to change the CPU context. When you
change the CPU context, the ‘‘SDA current process’’ is changed to the current
process on the ‘‘SDA current CPU’’ to synchronize CPU context and process
context. If no current process is on the ‘‘SDA current CPU,’’ the ‘‘SDA current
process’’ is undefined; no process context information will be available until you
set SDA process context to a specific process.
Type HELP PROCESS_CONTEXT for specific information about the ‘‘SDA
current process.’’
The following SDA commands change the ‘‘SDA current CPU’’:
Command Description
SET CPU cpu_id Changes the ‘‘SDA current CPU’’ to CPU cpu_id
SHOW CPU cpu_id Changes the ‘‘SDA current CPU’’ to CPU cpu_id
SHOW CRASH Changes the ‘‘SDA current CPU’’ to the CPU that induced the
system failure
If you select a process that is the current process on a CPU, the following
commands change the ‘‘SDA current CPU’’ to that CPU:
SET PROCESS name
SET PROCESS/INDEX=nn
SHOW PROCESS name
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