The following runtime options control storage allocation:
- STACK
- THREADSTACK
- LIBSTACK
- THREADHEAP
- HEAP
- ANYHEAP
- BELOWHEAP
- STORAGE
- HEAPPOOLS
z/OS Language Environment Programming Guide provides useful tips to assist with the tuning process. Appropriate tuning is necessary to avoid performance problems.
To generate a report of the storage a routine (or more specifically, an enclave) used during its run, specify the RPTSTG(ON) runtime option. The storage report, generated during enclave termination provides statistics that can help you understand how space is being consumed as the enclave runs. If storage management tuning is desired, the statistics can help you set the corresponding storage-related runtime options for future runs. The output is written to the Language Environment message file.
Neither the storage report nor the corresponding runtime options include the storage that Language Environment acquires during early initialization, before runtime options processing, and before the start of space management monitoring. In addition, Language Environment® does not report alternative Vendor Heap Manager activity.
Figure 1 and Figure 3 are examples of storage reports that are produced when RPTSTG(ON) is specified. The sections that follow these reports describe the contents of the reports.
Figure 1. Storage
report produced by run-time option RPTSTG(ON)
Storage Report for Enclave main 09/17/12 03:31:45 PM
Language Environment V02 R01.00
STACK statistics:
Initial size: 4096
Increment size: 4096
Maximum used by all concurrent threads: 7488
Largest used by any thread: 7488
Number of segments allocated: 2
Number of segments freed: 0
THREADSTACK statistics:
Initial size: 4096
Increment size: 4096
Maximum used by all concurrent threads: 3352
Largest used by any thread: 3352
Number of segments allocated: 6
Number of segments freed: 0
LIBSTACK statistics:
Initial size: 4096
Increment size: 4096
Maximum used by all concurrent threads: 0
Largest used by any thread: 0
Number of segments allocated: 0
Number of segments freed: 0
THREADHEAP statistics:
Initial size: 4096
Increment size: 4096
Maximum used by all concurrent threads: 0
Largest used by any thread: 0
Successful Get Heap requests: 0
Successful Free Heap requests: 0
Number of segments allocated: 0
Number of segments freed: 0
Figure 2. Storage report produced by run-time option RPTSTG(ON) (continued)
HEAP statistics:
Initial size: 49152
Increment size: 16384
Total heap storage used (sugg. initial size): 29112
Successful Get Heap requests: 251
Successful Free Heap requests: 218
Number of segments allocated: 1
Number of segments freed: 0
HEAP24 statistics:
Initial size: 8192
Increment size: 4096
Total heap storage used (sugg. initial size): 0
Successful Get Heap requests: 0
Successful Free Heap requests: 0
Number of segments allocated: 0
Number of segments freed: 0
ANYHEAP statistics:
Initial size: 32768
Increment size: 16384
Total heap storage used (sugg. initial size): 104696
Successful Get Heap requests: 28
Successful Free Heap requests: 15
Number of segments allocated: 6
Number of segments freed: 5
BELOWHEAP statistics:
Initial size: 8192
Increment size: 8192
Total heap storage used (sugg. initial size): 0
Successful Get Heap requests: 0
Successful Free Heap requests: 0
Number of segments allocated: 0
Number of segments freed: 0
Additional Heap statistics:
Successful Create Heap requests: 1
Successful Discard Heap requests: 1
Total heap storage used: 4912
Successful Get Heap requests: 3
Successful Free Heap requests: 3
Number of segments allocated: 2
Number of segments freed: 2
Largest number of threads concurrently active: 2
End of Storage ReportFigure 3 shows an example of a storage report that is produced with XPLINK
Figure 3. Storage
report produced by RPTSTG(ON) with XPLINK
Storage Report for Enclave main 09/17/12 03:31:45 PM
Language Environment V02 R01.00
STACK statistics:
Initial size: 131072
Increment size: 131072
Maximum used by all concurrent threads: 5416
Largest used by any thread: 5416
Number of segments allocated: 1
Number of segments freed: 0
THREADSTACK statistics:
Initial size: 4096
Increment size: 4096
Maximum used by all concurrent threads: 45536
Largest used by any thread: 6552
Number of segments allocated: 60
Number of segments freed: 0
XPLINK STACK statistics:
Initial size: 524288
Increment size: 131072
Largest used by any thread: 20400
Number of segments allocated: 1
Number of segments freed: 0
XPLINK THREADSTACK statistics:
Initial size: 131072
Increment size: 131072
Largest used by any thread: 22160
Number of segments allocated: 30
Number of segments freed: 0
LIBSTACK statistics:
Initial size: 4096
Increment size: 4096
Maximum used by all concurrent threads: 0
Largest used by any thread: 0
Number of segments allocated: 0
Number of segments freed: 0
THREADHEAP statistics:
Initial size: 4096
Increment size: 4096
Maximum used by all concurrent threads: 0
Largest used by any thread: 0
Successful Get Heap requests: 0
Successful Free Heap requests: 0
Number of segments allocated: 0
Number of segments freed: 0
HEAP statistics:
Initial size: 32768
Increment size: 32768
Total heap storage used (sugg. initial size): 286576
Successful Get Heap requests: 71
Successful Free Heap requests: 1
Number of segments allocated: 10
Number of segments freed: 0 Figure 4. Storage
report produced by RPTSTG(ON) with XPLINK (continued)
HEAP24 statistics:
Initial size: 8192
Increment size: 4096
Total heap storage used (sugg. initial size): 0
Successful Get Heap requests: 0
Successful Free Heap requests: 0
Number of segments allocated: 0
Number of segments freed: 0
ANYHEAP statistics:
Initial size: 16384
Increment size: 8192
Total heap storage used (sugg. initial size): 1139712
Successful Get Heap requests: 487
Successful Free Heap requests: 431
Number of segments allocated: 50
Number of segments freed: 36
BELOWHEAP statistics:
Initial size: 8192
Increment size: 4096
Total heap storage used (sugg. initial size): 0
Successful Get Heap requests: 0
Successful Free Heap requests: 0
Number of segments allocated: 0
Number of segments freed: 0
Additional Heap statistics:
Successful Create Heap requests: 0
Successful Discard Heap requests: 0
Total heap storage used: 0
Successful Get Heap requests: 0
Successful Free Heap requests: 0
Number of segments allocated: 0
Number of segments freed: 0
HEAPPOOLS Statistics:
Pool 1 size: 8 Get Requests: 3
Successful Get Heap requests: 1- 8 3
Pool 2 size: 32 Get Requests: 268
Successful Get Heap requests: 9- 16 36
Successful Get Heap requests: 17- 24 3
Successful Get Heap requests: 25- 32 229
Pool 3 size: 128 Get Requests: 186
Successful Get Heap requests: 33- 40 3
Successful Get Heap requests: 41- 48 8
Successful Get Heap requests: 49- 56 111
Successful Get Heap requests: 57- 64 4
Successful Get Heap requests: 65- 72 2
Successful Get Heap requests: 73- 80 4
Successful Get Heap requests: 81- 88 6
Successful Get Heap requests: 89- 96 2
Successful Get Heap requests: 97- 104 1
Successful Get Heap requests: 105- 112 5
Successful Get Heap requests: 113- 120 31
Successful Get Heap requests: 121- 128 9Figure 5. Storage
report produced by RPTSTG(ON) with XPLINK (continued)
Pool 4 size: 256 Get Requests: 38
Successful Get Heap requests: 137- 144 2
Successful Get Heap requests: 145- 152 2
Successful Get Heap requests: 153- 160 2
Successful Get Heap requests: 161- 168 1
Successful Get Heap requests: 169- 176 4
Successful Get Heap requests: 177- 184 4
Successful Get Heap requests: 185- 192 2
Successful Get Heap requests: 193- 200 2
Successful Get Heap requests: 201- 208 3
Successful Get Heap requests: 209- 216 2
Successful Get Heap requests: 217- 224 3
Successful Get Heap requests: 225- 232 3
Successful Get Heap requests: 233- 240 1
Successful Get Heap requests: 241- 248 3
Successful Get Heap requests: 249- 256 4
Pool 5.1 size: 1024 Get Requests: 230
Pool 5.2 size: 1024 Get Requests: 3
Pool 5.3 size: 1024 Get Requests: 5
Successful Get Heap requests: 257- 264 225
Successful Get Heap requests: 273- 280 2
Successful Get Heap requests: 281- 288 10
Successful Get Heap requests: 841- 848 1
Pool 6 size: 2048 Get Requests: 2
Successful Get Heap requests: 1113- 1120 1
Successful Get Heap requests: 1137- 1144 1
Requests greater than the largest cell size: 2
HEAPPOOLS Summary:
Specified Element Extent Cells Per Extents Maximum Cells In
Cell Size Size Percent Extent Allocated Cells Used Use
------------------------------------------------------------------------
8 16 10 204 1 1 0
32 40 10 81 3 226 225
128 136 10 24 4 88 77
256 264 10 12 1 1 0
1024 1032 10 4 57 228 227
1024 1032 10 4 1 2 0
1024 1032 10 4 1 3 0
2048 2056 10 4 1 2 2
------------------------------------------------------------------------
Suggested Percentages for current Cell Sizes:
HEAPP(ON,8,1,32,28,128,37,256,1,(1024,3),90,2048,13,0)
Suggested Cell Sizes:
HEAPP(ON,
32,,56,,88,,120,,128,,168,,
208,,248,,288,,848,,1144,,2080,)
Largest number of threads concurrently active: 11
End of Storage Report
The statistics for initial and incremental allocations of storage
types that have a corresponding runtime option differ from the runtime
option settings when their values have been rounded up by the implementation,
or when allocations larger than the amounts specified were required
during execution. All of the following are rounded up to an integral
number of double-words:
- Initial STACK allocations
- Initial allocations of THREADSTACK
- Initial allocations of all types of heap
- Incremental allocations of all types of stack and heap
The runtime options should be tuned appropriately to avoid performance problems. See z/OS Language Environment Programming Guide for tips on tuning.