[jboss-user] [Performance Tuning] - Re: JBoss 4.05 memory issue

bakry do-not-reply at jboss.com
Mon Dec 22 02:39:53 EST 2008

hi peter
thanks for the reply, I have looked at your presentation before (it was very helpfull)... here is what I got in the GC details during a load test on my server

23.382: [GC [PSYoungGen: 55462K->4583K(78848K)] 55462K->4583K(254976K), 0.0817857 secs]
23.464: [Full GC [PSYoungGen: 4583K->0K(78848K)] [PSOldGen: 0K->3770K(176128K)] 4583K->3770K(254976K) [PSPermGen: 9172K->9172K(20480K)], 0.2574611 secs]
36.571: [GC [PSYoungGen: 67584K->5088K(78848K)] 71354K->8858K(254976K), 0.0819799 secs]
49.827: [GC [PSYoungGen: 72672K->5776K(78848K)] 76442K->9546K(254976K), 0.0263934 secs]
59.113: [GC [PSYoungGen: 73360K->11253K(78848K)] 77130K->15313K(254976K), 0.0908562 secs]
65.952: [GC [PSYoungGen: 78837K->11256K(78848K)] 82897K->19543K(254976K), 0.0962789 secs]
73.377: [GC [PSYoungGen: 78840K->11260K(69248K)] 87127K->27342K(245376K), 0.0890153 secs]
77.938: [GC [PSYoungGen: 69244K->19542K(78144K)] 85326K->35624K(254272K), 0.0236485 secs]
83.007: [GC [PSYoungGen: 76822K->18333K(80960K)] 92904K->37861K(257088K), 0.1007859 secs]
91.264: [GC [PSYoungGen: 75229K->16045K(82432K)] 94757K->40041K(258560K), 0.0874944 secs]
97.515: [GC [PSYoungGen: 72941K->6440K(100288K)] 96937K->41397K(276416K), 0.1227819 secs]
106.366: [GC [PSYoungGen: 97512K->3956K(126144K)] 132469K->43596K(302272K), 0.0982573 secs]
114.011: [GC [PSYoungGen: 104692K->5246K(171584K)] 144332K->46515K(347712K), 0.0972135 secs]
121.696: [GC [PSYoungGen: 151422K->4595K(171200K)] 192691K->50596K(347328K), 0.0997297 secs]
131.357: [GC [PSYoungGen: 150771K->4244K(254464K)] 196772K->53941K(430592K), 0.1022893 secs]
288.364: [GC [PSYoungGen: 238164K->8666K(235968K)] 287861K->61652K(412096K), 0.0884445 secs]
297.527: [GC [PSYoungGen: 235930K->12210K(235520K)] 288916K->72886K(411648K), 0.0970622 secs]
300.876: [GC [PSYoungGen: 232775K->22514K(243712K)] 293451K->91712K(419840K), 0.0896641 secs]
302.277: [GC [PSYoungGen: 243698K->29180K(300160K)] 312896K->116730K(476288K), 0.1172576 secs]
304.287: [GC [PSYoungGen: 299769K->28943K(299968K)] 387320K->141716K(476096K), 0.1029239 secs]
306.433: [GC [PSYoungGen: 299919K->6831K(310080K)] 412692K->146559K(486208K), 0.1055606 secs]
308.730: [GC [PSYoungGen: 273775K->5377K(309120K)] 413503K->148026K(485248K), 0.0176229 secs]
311.867: [GC [PSYoungGen: 272321K->4171K(310080K)] 414970K->150445K(486208K), 0.0780572 secs]
316.559: [GC [PSYoungGen: 272907K->2352K(310912K)] 419181K->150306K(487040K), 0.0814960 secs]
321.431: [GC [PSYoungGen: 272816K->2224K(311808K)] 420770K->151770K(487936K), 0.0195984 secs]
326.477: [GC [PSYoungGen: 274352K->2376K(312576K)] 423898K->153514K(488704K), 0.0181888 secs]
331.359: [GC [PSYoungGen: 276232K->2224K(313536K)] 427370K->155030K(489664K), 0.0821171 secs]
336.450: [GC [PSYoungGen: 278192K->2256K(314688K)] 430998K->156642K(490816K), 0.0190569 secs]
336.469: [Full GC[Unloading class sun.reflect.GeneratedMethodAccessor773]
[Unloading class sun.reflect.GeneratedConstructorAccessor259]
[Unloading class sun.reflect.GeneratedConstructorAccessor154]
[Unloading class sun.reflect.GeneratedConstructorAccessor289]
[PSYoungGen: 2256K->0K(314688K)] [PSOldGen: 154386K->109726K(376832K)] 156642K->109726K(691520K) [PSPermGen: 54285K->54285K(110592K)], 2.5979181 secs]
342.507: [GC [PSYoungGen: 278400K->5954K(311872K)] 388126K->115680K(688704K), 0.0196707 secs]
345.645: [GC [PSYoungGen: 286978K->8429K(315328K)] 396704K->121705K(692160K), 0.0185399 secs]
349.908: [GC [PSYoungGen: 290925K->8000K(315328K)] 404201K->127828K(692160K), 0.0185565 secs]
354.791: [GC [PSYoungGen: 296960K->2320K(319744K)] 416788K->127720K(696576K), 0.0176147 secs]
360.372: [GC [PSYoungGen: 293648K->5125K(323840K)] 419048K->130525K(700672K), 0.0168338 secs]
365.858: [GC [PSYoungGen: 301445K->5856K(304576K)] 426845K->131256K(681408K), 0.0808504 secs]
371.278: [GC [PSYoungGen: 304544K->7888K(325184K)] 429944K->134885K(702016K), 0.0170485 secs]
376.939: [GC [PSYoungGen: 308560K->7152K(323648K)] 435557K->134148K(700480K), 0.0178370 secs]
382.394: [GC [PSYoungGen: 307824K->8848K(327552K)] 434820K->135844K(704384K), 0.0188606 secs]
388.103: [GC [PSYoungGen: 314896K->10416K(326656K)] 441892K->137412K(703488K), 0.0173568 secs]
393.822: [GC [PSYoungGen: 316464K->13413K(330368K)] 443460K->140409K(707200K), 0.0186272 secs]
399.556: [GC [PSYoungGen: 323429K->13744K(323776K)] 450425K->140740K(700608K), 0.0183015 secs]
405.175: [GC [PSYoungGen: 323760K->16693K(327360K)] 450756K->143689K(704192K), 0.0190493 secs]
410.909: [GC [PSYoungGen: 322229K->17024K(322560K)] 449225K->144020K(699392K), 0.0191946 secs]
416.457: [GC [PSYoungGen: 322560K->18713K(324352K)] 449556K->145710K(701184K), 0.0195976 secs]
422.053: [GC [PSYoungGen: 318361K->20256K(319936K)] 445358K->147252K(696768K), 0.0193531 secs]
427.636: [GC [PSYoungGen: 319904K->21872K(320128K)] 446900K->148868K(696960K), 0.0203252 secs]
433.068: [GC [PSYoungGen: 313840K->23456K(315456K)] 440836K->150452K(692288K), 0.0214092 secs]

as you can see the GC is running fine and freeing young gen frequently during the run, also it goes through one cycle of major run and freed the old gen.... however at the end of the run, the server still have 700MB as total memory and 480M as Free Memory (seen through the jboss web console and unix command prstat).... I wonder why is that... what I am expecting is that the server should run a major GC (maybe not immediately after my run, but some time after that) and return some of the free memory to the OS, sometimes I run into situation where my total memory equals 1.2G and the free = 1G !!!


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