Accelerator Manual (G06.27+, H06.04+, J06.03+)

Preparing Your Program for TNS/R Systems
Accelerator Manual—527303-003
2-15
Misalignment Handling
Because a process can run for a long time, the tracing facility samples the process
(that is, checks its exception data) periodically (approximately once an hour). If the
process recorded an exception since the previous sample, the tracing facility records
an entry in the EMS log. If the process ends, and any exception has occurred since the
last sample, the operating system produces a final Event Management Service (EMS)
event.
The EMS event includes:
•
The process’s exception count
•
Details about one misaligned-address exception, including the program address,
data address, and relevant code-file names
Sampling is short and infrequent enough to avoid flooding the EMS log, even for a
continuous process with many misaligned-address exceptions. One sample logs a
maximum of 100 events, and at most one event is logged for any process.
If misaligned-address exceptions occur in different periods of a process, the operating
system produces multiple EMS events for the same process, and these EMS events
might have different program addresses.
For more information about EMS events or the EMS log, see the EMS Reference
Manual.
Misalignment Handling
Misalignment handling is determined by the following SCF attributes, which are set
system-wide (that is, for all processors in the node) by the persons who configure the
system:
•
MISALIGNLOG
•
TNSMISALIGN
•
NATIVEATOMICMISALIGN (applies only to programs running in TNS/R native
mode, and therefore, does not apply to the Accelerator)
MISALIGNLOG enables or disables the tracing facility.
TNSMISALIGN applies to all programs running in TNS mode or accelerated mode, but
not to programs running in TNS/R native mode.
Table 2-1, TNS Misalignment Handling Methods,
on page 2-16 lists and describes the
possible settings for TNSMISALIGN. Each setting represents a misalignment handling
method. For more information about TNSMISALIGN, see the SCF Reference Manual
for the Kernel Subsystem.