JVM Memory Tuning Advice

Question

Please what memory tuning advise would you suggest given the GC log below with a system currently running on these params, taking into consideration the Machine recieves high frequency data that takes a about 6ms to process.

Thanks in Advance.

java -Xms4144m -Xmx4144m -XX:+UseParNewGC -XX:+CMSClassUnloadingEnabled -XX:CMSFullGCsBeforeCompaction=1 -XX:+PrintGCDetails -Xloggc:gc.log -verbose:gc -XX:SurvivorRatio=4 -XX:+UseCompressedOop

GC Logs

198.341: [GC 198.341: [ParNew: 1178752K->235712K(1178752K), 0.7930435 secs] 2653227K->1913561K(4007744K), 0.7931001 secs] [Times: user=1.36 sys=0.03, real=0.79 secs] 
219.946: [GC 219.946: [ParNew: 1178752K->235712K(1178752K), 0.6662757 secs] 2856601K->2095809K(4007744K), 0.6663335 secs] [Times: user=1.23 sys=0.03, real=0.67 secs] 
230.170: [GC 230.170: [ParNew: 1178752K->235712K(1178752K), 0.7158400 secs] 3038849K->2235472K(4007744K), 0.7158940 secs] [Times: user=1.39 sys=0.02, real=0.72 secs] 
242.243: [GC 242.243: [ParNew: 1178752K->235712K(1178752K), 0.8650113 secs] 3178512K->2538982K(4007744K), 0.8650603 secs] [Times: user=1.64 sys=0.06, real=0.87 secs] 
257.200: [GC 257.200: [ParNew: 1178752K->235712K(1178752K), 0.6999034 secs] 3482022K->2698292K(4007744K), 0.6999583 secs] [Times: user=1.30 sys=0.03, real=0.70 secs] 
271.794: [GC 271.794: [ParNew: 1178752K->235712K(1178752K), 0.8674328 secs] 3641332K->2929779K(4007744K), 0.8674890 secs] [Times: user=1.53 sys=0.08, real=0.87 secs] 
285.540: [GC 285.540: [ParNew: 1178752K->1178752K(1178752K), 0.0000200 secs]285.541: [Tenured: 2694067K->2687296K(2828992K), 8.3795756 secs] 3872819K->2687296K(4007744K), [Perm : 75186K->75186K(75328K)], 8.3796871 secs] [Times: user=8.36 sys=0.00, real=8.38 secs] 
307.287: [GC 307.287: [ParNew: 943040K->943040K(1178752K), 0.0000216 secs]307.287: [Tenured: 2687296K->2828991K(2828992K), 8.8158385 secs] 3630336K->2875360K(4007744K), [Perm : 75195K->75195K(75328K)], 8.8159306 secs] [Times: user=8.78 sys=0.03, real=8.82 secs] 
331.624: [Full GC 331.624: [Tenured: 2828991K->2828991K(2828992K), 9.6792290 secs] 4007743K->2956484K(4007744K), [Perm : 75197K->75193K(75328K)], 9.6792896 secs] [Times: user=9.64 sys=0.03, real=9.68 secs] 
355.683: [Full GC 355.683: [Tenured: 2828991K->2828991K(2828992K), 8.6649544 secs] 4007743K->3189624K(4007744K), [Perm : 75195K->75195K(75328K)], 8.6650138 secs] [Times: user=8.63 sys=0.00, real=8.66 secs] 
375.500: [Full GC 375.500: [Tenured: 2828991K->2828991K(2828992K), 9.0546364 secs] 4007743K->3369414K(4007744K), [Perm : 75195K->75195K(75328K)], 9.0546949 secs] [Times: user=9.03 sys=0.02, real=9.05 secs] 
394.217: [Full GC 394.217: [Tenured: 2828991K->2828991K(2828992K), 9.3253515 secs] 4007743K->3502795K(4007744K), [Perm : 75197K->75197K(75328K)], 9.3254103 secs] [Times: user=9.23 sys=0.05, real=9.32 secs] 
411.511: [Full GC 411.511: [Tenured: 2828991K->2828991K(2828992K), 11.2295533 secs] 4007743K->3544789K(4007744K), [Perm : 75199K->75199K(75328K)], 11.2296119 secs] [Times: user=11.24 sys=0.02, real=11.23 secs] 
429.802: [Full GC 429.802: [Tenured: 2828991K->2828991K(2828992K), 9.7181375 secs] 4007743K->3649219K(4007744K), [Perm : 75199K->75199K(75328K)], 9.7182127 secs] [Times: user=9.69 sys=0.02, real=9.72 secs] 
445.271: [Full GC 445.271: [Tenured: 2828991K->2828991K(2828992K), 9.8961275 secs] 4007743K->3725989K(4007744K), [Perm : 75200K->75200K(75328K)], 9.8961886 secs] [Times: user=9.86 sys=0.02, real=9.90 secs] 
459.824: [Full GC 459.824: [Tenured: 2828992K->2828992K(2828992K), 9.9093299 secs] 4007743K->3788320K(4007744K), [Perm : 75200K->75200K(75264K)], 9.9093896 secs] [Times: user=9.84 sys=0.03, real=9.91 secs] 
472.905: [Full GC 472.905: [Tenured: 2828992K->2828991K(2828992K), 11.9256624 secs] 4007743K->3820926K(4007744K), [Perm : 75200K->75125K(75264K)], 11.9257166 secs] [Times: user=11.91 sys=0.00, real=11.93 secs] 
488.573: [Full GC 488.573: [Tenured: 2828991K->2828991K(2828992K), 10.0481444 secs] 4007743K->3858495K(4007744K), [Perm : 75126K->75126K(75264K)], 10.0482011 secs] [Times: user=10.03 sys=0.02, real=10.05 secs] 
501.588: [Full GC 501.588: [Tenured: 2828991K->2828991K(2828992K), 10.0523092 secs] 4007743K->3894229K(4007744K), [Perm : 75126K->75126K(75264K)], 10.0523631 secs] [Times: user=10.02 sys=0.05, real=10.05 secs] 
513.358: [Full GC 513.358: [Tenured: 2828991K->2828991K(2828992K), 10.4441345 secs] 4007743K->3922499K(4007744K), [Perm : 75126K->75126K(75264K)], 10.4441888 secs] [Times: user=10.41 sys=0.05, real=10.44 secs] 
525.149: [Full GC 525.149: [Tenured: 2828991K->2828992K(2828992K), 12.3326697 secs] 4007743K->3933477K(4007744K), [Perm : 75127K->75123K(75264K)], 12.3327241 secs] [Times: user=12.30 sys=0.02, real=12.33 secs] 
538.518: [Full GC 538.518: [Tenured: 2828992K->2828992K(2828992K), 10.1793883 secs] 4007744K->3951837K(4007744K), [Perm : 75124K->75124K(75264K)], 10.1794431 secs] [Times: user=10.16 sys=0.00, real=10.18 secs] 
549.421: [Full GC 549.421: [Tenured: 2828992K->2828992K(2828992K), 10.2044623 secs] 4007743K->3966013K(4007744K), [Perm : 75124K->75124K(75264K)], 10.2045185 secs] [Times: user=10.16 sys=0.03, real=10.20 secs] 
560.138: [Full GC 560.138: [Tenured: 2828992K->2828992K(2828992K), 10.2487167 secs] 4007743K->3977058K(4007744K), [Perm : 75125K->75125K(75264K)], 10.2487719 secs] [Times: user=10.22 sys=0.03, real=10.25 secs] 
570.809: [Full GC 570.809: [Tenured: 2828992K->2828991K(2828992K), 12.3747337 secs] 4007743K->3982653K(4007744K), [Perm : 75125K->75125K(75264K)], 12.3747909 secs] [Times: user=12.34 sys=0.03, real=12.37 secs] 
583.616: [Full GC 583.616: [Tenured: 2828991K->2828991K(2828992K), 10.2968728 secs] 4007743K->3989103K(4007744K), [Perm : 75125K->75125K(75264K)], 10.2969323 secs] [Times: user=10.22 sys=0.05, real=10.30 secs] 
594.116: [Full GC 594.116: [Tenured: 2828991K->2828991K(2828992K), 10.2502126 secs] 4007743K->3994344K(4007744K), [Perm : 75126K->75126K(75264K)], 10.2502671 secs] [Times: user=10.24 sys=0.02, real=10.25 secs] 
604.508: [Full GC 604.508: [Tenured: 2828991K->2828991K(2828992K), 10.3733315 secs] 4007743K->3998499K(4007744K), [Perm : 75127K->75127K(75264K)], 10.3733868 secs] [Times: user=10.30 sys=0.06, real=10.37 secs] 
614.984: [Full GC 614.984: [Tenured: 2828991K->2828991K(2828992K), 12.4043694 secs] 4007743K->4000611K(4007744K), [Perm : 75127K->75118K(75264K)], 12.4044216 secs] [Times: user=12.36 sys=0.02, real=12.40 secs] 
627.474: [Full GC 627.474: [Tenured: 2828991K->2828991K(2828992K), 10.4267471 secs] 4007743K->4002564K(4007744K), [Perm : 75118K->75118K(75264K)], 10.4268039 secs] [Times: user=10.31 sys=0.05, real=10.43 secs] 
637.975: [Full GC 637.975: [Tenured: 2828991K->2828991K(2828992K), 10.2774899 secs] 4007743K->4004685K(4007744K), [Perm : 75118K->75118K(75264K)], 10.2775510 secs] [Times: user=10.19 sys=0.05, real=10.28 secs] 
648.284: [Full GC 648.284: [Tenured: 2828991K->2828991K(2828992K), 10.2766971 secs] 4007736K->4005877K(4007744K), [Perm : 75118K->75118K(75264K)], 10.2767509 secs] [Times: user=10.22 sys=0.03, real=10.28 secs] 
658.585: [Full GC 658.585: [Tenured: 2828991K->2828991K(2828992K), 12.4831705 secs] 4007743K->4005966K(4007744K), [Perm : 75118K->75118K(75264K)], 12.4832232 secs] [Times: user=12.42 sys=0.03, real=12.48 secs] 
671.090: [Full GC 671.090: [Tenured: 2828991K->2828991K(2828992K), 10.4432966 secs] 4007743K->4006356K(4007744K), [Perm : 75118K->75118K(75264K)], 10.4433494 secs] [Times: user=10.31 sys=0.03, real=10.44 secs] 
681.555: [Full GC 681.555: [Tenured: 2828991K->2828991K(2828992K), 10.7448251 secs] 4007743K->4006368K(4007744K), [Perm : 75119K->75119K(75264K)], 10.7448778 secs] [Times: user=10.72 sys=0.02, real=10.74 secs] 
692.316: [Full GC 692.316: [Tenured: 2828991K->2828991K(2828992K), 10.2663540 secs] 4007743K->4006774K(4007744K), [Perm : 75136K->75136K(75264K)], 10.2664250 secs] [Times: user=10.25 sys=0.00, real=10.27 secs] 
702.608: [Full GC 702.608: [Tenured: 2828991K->2828992K(2828992K), 12.4610859 secs] 4007743K->4006891K(4007744K), [Perm : 75140K->75140K(75264K)], 12.4611370 secs] [Times: user=12.42 sys=0.03, real=12.46 secs] 
715.087: [Full GC 715.087: [Tenured: 2828992K->2828992K(2828992K), 10.3067777 secs] 4007743K->4007227K(4007744K), [Perm : 75140K->75140K(75264K)], 10.3068309 secs] [Times: user=10.22 sys=0.03, real=10.31 secs] 
725.402: [Full GC 725.402: [Tenured: 2828992K->2828992K(2828992K), 10.2705306 secs] 4007743K->4007320K(4007744K), [Perm : 75152K->75152K(75264K)], 10.2706022 secs] [Times: user=10.20 sys=0.11, real=10.27 secs] 
735.678: [Full GC 735.678: [Tenured: 2828992K->2828992K(2828992K), 10.3012637 secs] 4007744K->4007310K(4007744K), [Perm : 75152K->75152K(75264K)], 10.3013231 secs] [Times: user=10.28 sys=0.00, real=10.30 secs] 
745.986: [Full GC 745.986: [Tenured: 2828992K->2828991K(2828992K), 12.5238366 secs] 4007744K->4007281K(4007744K), [Perm : 75152K->75152K(75264K)], 12.5238903 secs] [Times: user=12.45 sys=0.01, real=12.52 secs] 
758.516: [Full GC 758.516: [Tenured: 2828991K->2828991K(2828992K), 10.2712146 secs] 4007743K->4007484K(4007744K), [Perm : 75152K->75152K(75264K)], 10.2712660 secs] [Times: user=10.27 sys=0.02, real=10.27 secs] 
768.792: [Full GC 768.792: [Tenured: 2828991K->2828991K(2828992K), 10.2586840 secs] 4007743K->4007470K(4007744K), [Perm : 75152K->75152K(75264K)], 10.2587353 secs] [Times: user=10.19 sys=0.03, real=10.26 secs] 
779.064: [Full GC 779.064: [Tenured: 2828991K->2828991K(2828992K), 10.4511437 secs] 4007743K->4007399K(4007744K), [Perm : 75152K->75152K(75264K)], 10.4511969 secs] [Times: user=10.34 sys=0.02, real=10.45 secs] 
789.525: [Full GC 789.525: [Tenured: 2828991K->2828991K(2828992K), 12.4538596 secs] 4007743K->4007551K(4007744K), [Perm : 75152K->75152K(75264K)], 12.4539062 secs] [Times: user=12.41 sys=0.03, real=12.45 secs] 
801.997: [Full GC 801.997: [Tenured: 2828991K->2828991K(2828992K), 10.3025233 secs] 4007743K->4007417K(4007744K), [Perm : 75152K->75152K(75264K)], 10.3025765 secs] [Times: user=10.27 sys=0.00, real=10.30 secs] 

Answer 1

Your application leaks memory (amount of free space after collection decreases monotonously). If it is to a leak, when you should increase memory, try 8GiB to begin with.

In addition -XX:+CMSClassUnloadingEnabled -XX:CMSFullGCsBeforeCompaction=1 are applicable to CMS collector, but you are using ParNew + Single threaded MSC collector.

If your want to use CMS (Concurrent Mark Sweep) add -XX:+UseConcMarkSweepGC.

Take a look at JVM GC options cheatsheet to see more details about available tuning options.