Performance Impact of Chunk Size

Java GC Tutorials - Herong's Tutorial Examples

∟Garbage Collection Performance Test Program

∟Performance Impact of Chunk Size

This section provides tests to find out performance impact of the chunk size (number of objects created and released in a single test run). The throughput performance seems to be not impacted by the chunk size, if some throughput jumps are ignored.

While running tests with GCPerformance.java, I also noticed an interesting behavior when using a lower test chunk size.

Test 1 - Running GCPerformance.java with chunk size of 16 objects. For some test junks, the throughput jumped from 4000 to 5333 objects:

herong> java -Xms1600m -Xmx1600m GCPerformance 1024 32 16 0 32

Parameters: Size=1024KB, Base=32, Chunk=16, Wait=0ms, Warmup=32
Real:Exec  Lat.     Throughput      Total:Free  Proc.
Time:Time  ms/o  Ave:Min:Max:Chunk   Mem.:Mem.   Obj.
4:4  250  4000:4000:4000:4000  1638400:1145616  16
24:24  1250  1333:800:4000:800  1638400:1111822  32
28:28  1250  1714:800:4000:4000  1638400:1079054  48
33:33  1250  1939:800:4000:3200  1638400:1046286  64
37:37  1250  2162:800:4000:4000  1638400:1013518  80
42:42  1250  2285:800:4000:3200  1638400:980750  96
46:46  1250  2434:800:4000:4000  1638400:947982  112
50:50  1250  2560:800:4000:4000  1638400:915214  128
59:59  1250  2440:800:4000:1777  1638400:1538717  144
64:64  1250  2500:800:4000:3200  1638400:1505949  160
69:69  1250  2550:800:4000:3200  1638400:1473181  176
73:73  1250  2630:800:4000:4000  1638400:1440413  192
76:76  1250  2736:800:5333:5333  1638400:1407645  208
79:79  1250  2835:800:5333:5333  1638400:1374877  224
...
127:127  1250  3275:800:5333:4000  1638400:981156  416
131:131  1250  3297:800:5333:4000  1638400:948388  432
134:134  1250  3343:800:5333:5333  1638400:915620  448
                             ----
       Throughput jumped here - |
...

Test 2 - Running GCPerformance.java with chunk size of 24 objects. For some test runs, the throughput jumped from 4000 to 4800 objects:

herong> java -Xms1600m -Xmx1600m GCPerformance 1024 32 24 0 32

Parameters: Size=1024KB, Base=32, Chunk=24, Wait=0ms, Warmup=32
Real:Exec  Lat.     Throughput      Total:Free  Proc.
Time:Time  ms/o  Ave:Min:Max:Chunk   Mem.:Mem.   Obj.
7:7  291  3428:3428:3428:3428  1638400:1227479  24
30:30  958  1600:1043:3428:1043  1638400:1177301  48
38:38  958  1894:1043:3428:3000  1638400:1128149  72
45:45  958  2133:1043:3428:3428  1638400:1078997  96
52:52  958  2307:1043:3428:3428  1638400:1029845  120
57:57  958  2526:1043:4800:4800  1638400:980693  144
63:63  958  2666:1043:4800:4000  1638400:931541  168
...
104:104  958  3000:1043:4800:4000  1638400:1276579  312
110:110  958  3054:1043:4800:4000  1638400:1227427  336
115:115  958  3130:1043:4800:4800  1638400:1178275  360
...
180:180  958  3333:1043:4800:4000  1638400:1325201  600
186:186  958  3354:1043:4800:4000  1638400:1276049  624
191:191  958  3392:1043:4800:4800  1638400:1226897  648
                             ----
       Throughput jumped here - |
...

Test 3 - Running GCPerformance.java with chunk size of 32 objects. For some test runs, the throughput jumped from 516 to 695 objects:

herong> java -Xms1600m -Xmx1600m GCPerformance 1024 32 32 0 32

Parameters: Size=1024KB, Base=32, Chunk=32, Wait=0ms, Warmup=32
Real:Exec  Lat.     Throughput      Total:Free  Proc.
Time:Time  ms/o  Ave:Min:Max:Chunk   Mem.:Mem.   Obj.
8:8  250  4000:4000:4000:4000  1638400:1374975  32
31:31  718  2064:1391:4000:1391  1638400:1308413  64
39:39  718  2461:1391:4000:4000  1638400:1242877  96
47:47  718  2723:1391:4000:4000  1638400:1177341  128
55:55  718  2909:1391:4000:4000  1638400:1111805  160
63:63  718  3047:1391:4000:4000  1638400:1046269  192
71:71  718  3154:1391:4000:4000  1638400:980733  224
79:79  718  3240:1391:4000:4000  1638400:915197  256
...
107:107  718  3289:1391:4571:4000  1638400:1374889  352
114:114  718  3368:1391:4571:4571  1638400:1309353  384
...
138:138  718  3478:1391:4571:4000  1638400:1112745  480
146:146  718  3506:1391:4571:4000  1638400:1047209  512
153:153  718  3555:1391:4571:4571  1638400:981673  544
                             ----
       Throughput jumped here - |
...

Test result summary

Chunk Size   Ave Throughput   Max Throughput
----------   --------------   --------------
    32 obj             3555             4571
    24 obj             3392             4800
    16 obj             3343             5333