6. DATA SOURCES › 6.10 APPC/MVS Overview › 6.10.2 APPC/MVS Transaction Response Time › 6.10.2.1 Detail APPC Transaction Response Time Analysis
6.10.2.1 Detail APPC Transaction Response Time Analysis
The DETAIL time-span APPC/MVS Transaction file (BATATP)
contains measurements that describe both the Total Response
Time (ATPTRSTM) of an APPC/MVS ASCH-scheduled TP and the
component parts, listed below:
ATPTNSTM - APPC Transit Time
ATPINQTM - ASCH Queue Time
ATPEXCTM - TP Execution Time
One additional component of TP response time that is not
captured is the network delay time incurred between the time
the partner TP issues the allocate request and the time that
the APPC/MVS address space receives the request.
APPC TRANSIT TIME
APPC Transit Time (ATPTNSTM) should be minimal. This is
the duration bounded by the time that APPC/MVS first
receives the allocate request and the time that the request
is passed to the ASCH scheduler. During this time, the
APPC address space performs symbolic name translation (only
for requests from partner TPs in the local environment),
security authorization checking, mapping of the TP name to
the appropriate profile data set, and extraction of the
information required by the ASCH scheduler.
If this component of Total Response Time is excessive, it
is probably due to excessive search time required to find
the TP information in the profile data set. This search
time can be minimized by creating more profile data sets
and limiting the number of TPs in each.
ASCH QUEUE TIME
ASCH Queue Time (ATPINQTM) is the easiest to control. Each
ASCH-scheduled TP is assigned to a TP Class (ATPCLASS).
The allowable TP Classes are defined in the ASCHPMxx
member(s) of SYS1.PROCLIB. Each TP Class has the following
performance specifications:
The MIN and MAX keywords specify the minimum and maximum
number of initiators for the TP Class. The allowable
ranges and defaults are:
MIN MAX
---------- ----------
DEFAULT 0 1
RANGE 0 - 64,000 1 - 64,000
The RESPGOAL (response goal) keyword specifies, in seconds,
the acceptable amount of ASCH queue and TP execution time
for the TP Class. The ASCH scheduler uses this value,
compared to the real queue and execution times of TPs of
the class, to determine whether to create additional
initiators for the TP class. The range and default values
for RESPGOAL are:
RESPGOAL
----------------------------------------
DEFAULT 1 second
RANGE 0.000001 - 31,536,000 seconds (365 days)
The response goal value should be set to the average run
time for TPs of the class. IBM points out that some
reasonable amount of queue delay time should be included to
provide for the time required by the ASCH scheduler to
create and terminate initiators.
If excessive ASCH Queue Time values are encountered for TPs
of a particular class, the MAX initiator value may be too
low for the quantity of TPs requested. Additionally, if
the RESPGOAL value is set too high, ASCH will not be
compelled to create additional initiators and will instead
allow requests to wait in the queue, especially if the
system is strained and other TP classes have more stringent
response goals.
TP EXECUTION TIME
The final component of Total Response Time is TP Execution
Time (ATPEXCTM). This is completely dependent upon the
nature of the program executed. This component should be
analyzed to ensure that the TP Class used is correct for
the TP. TPs with typically long execution times should not
be assigned to a TP Class with a short response goal.
TP Type (STP/MTP/MSH) (ATPTYPE) should be considered when
analyzing TP response time. Standard TPs (ATPTYPE='STP')
are initiated for each inbound allocation request while
multi-trans TPs (ATPTYPE='MTP' and 'MSH') remain in
execution between requests. The shell portion of
multi-trans TPs (ATPTYPE='MTP' and 'MSH') are not good
candidates for response time analysis because the total
response time is equal to an estimate of the shell's
execution time.
