hi, Christopher Schultz, Pid, Jeffrey Janner Thanks for your reply.
Are you using a 64-bit or 32-bit JVM?
yes, that is 64-bit JVM.
What is the command you used to produce your jstat output?
Well, the comand is
[root]# jstat -gc {tomcat pid} 3000
that command means every 3 seconds to print out the status of garbage
collections.
What is "PC" ?
command (jstat -gc {tomcat pid} 3000) can traces the following areas
of memory what is allocated and used.
S0C Current survivor space 0 capacity (KB).
S1C Current survivor space 1 capacity (KB).
S0U Survivor space 0 utilization (KB).
S1U Survivor space 1 utilization (KB).
EC Current eden space capacity (KB).
EU Eden space utilization (KB).
OC Current old space capacity (KB).
OU Old space utilization (KB).
PC Current permanent space capacity (KB).
PU Permanent space utilization (KB).
YGC Number of young generation GC Events.
YGCT Young generation garbage collection time.
FGC Number of full GC events.
FGCT Full garbage collection time.
GCT Total garbage collection time.
Can you clarify this last statement? When did the first full GC take place? When did the second? When did the third?
According to the following csv data, we can see full-gc occurred at a time like this.
The 1st full-gc tomcat takes place at tomcat is starting. The 2th full-gc tomcat takes place at 11:48AM The 3th full-gc tomcat takes place at 1:23 PM The 4th full-gc tomcat takes place at 2:49 PM The 5th full-gc tomcat takes place at 4:24 PM The 6th full-gc tomcat takes place at 4:33 PM After 7th full-gc , basically 1 full-gc at 1 minutes will be occurred. is it normal? Is it because the programm of webapp not well, leading to memory leak? thanks ! ============================CSV data start ================================ systime,S0C,S1C,S0U,S1U,EC,EU,OC,OU,PC,PU,YGC,YGCT,FGC,FGCT,GCT10:56 AM,9600,3392,0,3369.3,53568,36562.3,699072,481787.7,61184,61167,249,3.148,1,0.005,3.153 11:48 AM,4032,3520,0,3520,39616,0,699072,697526,67712,67573.5,385,4.849,2,0.005,4.854 1:23 PM,2496,2496,0,0,29568,5620.2,699072,100281.5,71360,71236.5,1003,10.057,3,3.48,13.537 2:49 PM,2624,2624,0,0,27712,12302,679936,74349.4,78080,71771.3,1898,15.979,4,3.962,19.941 4:07 PM,3392,3712,1664,0,50496,28601.3,688000,109525.6,78080,74945.2,2804,21.46,5,4.567,26.027 4:24 PM,4480,2304,0,0,77632,27240.9,656960,103414.1,78080,75622.1,3107,23.191,6,4.943,28.134 4:33 PM,4160,2304,0,0,78144,25196.7,658752,98731.2,78080,76421.6,3365,24.604,7,5.329,29.933 4:41 PM,5568,3008,0,2952.4,103424,96055.6,606976,69788.7,78080,74229.1,3591,25.889,8,5.742,31.631 4:42 PM,7360,10176,0,0,174464,0,652544,91210.1,86016,86010.7,3620,26.067,10,6.081,32.148 4:42 PM,15552,16448,0,5850.8,174016,0,672448,81577.6,86016,86015.8,3625,26.128,11,6.454,32.582 4:42 PM,15552,15744,0,0,176640,47946.3,681536,57596.5,86016,84716.7,3626,26.133,12,7.041,33.174 4:43 PM,19520,19200,0,0,179328,12770.2,681728,55882.2,86016,84680.4,3637,26.329,14,7.634,33.963 4:44 PM,21376,20608,0,0,181504,13683.9,681600,55718.4,86016,84905.3,3653,26.507,16,8.276,34.784 4:45 PM,19712,20416,0,0,183104,4838.1,684288,55907,86016,85078.2,3670,26.686,18,8.922,35.608 4:45 PM,18112,19264,5882.8,0,183616,116840,691264,61653.6,86016,84820.4,3680,26.769,20,9.42,36.189 4:46 PM,28032,26688,0,0,181120,5398.8,687232,56195.2,86016,84834.2,3695,26.922,22,9.954,36.876 4:47 PM,23488,24448,0,0,182208,17955.5,689728,56704.2,86016,84915,3712,27.101,24,10.467,37.568 4:48 PM,22400,6528,0,6496,182464,21955.4,691776,57561.6,86016,85184,3721,27.184,26,11.015,38.198 4:48 PM,21376,22208,0,0,182912,9686.2,691200,55718.6,86016,84904.3,3734,27.314,28,11.578,38.892 4:49 PM,23616,22720,0,0,184640,5352.7,692608,55948.2,86016,85087.2,3749,27.473,30,12.118,39.592 4:49 PM,22272,21696,0,0,185920,9033.2,693824,56161,86016,84535,3757,27.545,32,12.618,40.164 4:50 PM,23104,23936,0,0,184448,10825.1,694464,56030.5,86016,84909.3,3772,27.709,34,13.122,40.831 4:51 PM,23360,24064,0,0,183872,6675.4,695232,56231,86016,84901.6,3784,27.828,36,13.631,41.459 4:51 PM,23040,23552,0,7904,183680,0,695232,56231,86016,86015.7,3795,27.952,37,13.631,41.583 4:51 PM,23168,23808,0,5856,183488,154538.9,696192,56856.7,86016,85007.5,3797,27.963,38,14.157,42.12 4:52 PM,25536,26368,0,0,183488,9536.2,699072,70891.1,86016,84992.9,3808,28.079,40,14.679,42.757 4:52 PM,21760,22784,6688,0,189760,0,699072,70891.1,86016,86015.9,3816,28.414,41,14.679,43.093 4:52 PM,23296,22784,0,0,189760,9992.9,695616,56272.1,86016,84713.9,3817,28.418,42,15.221,43.639 4:53 PM,25408,24320,0,0,192448,4086.7,695936,56385.9,86016,84589.2,3835,28.628,44,15.728,44.356 4:54 PM,25408,24320,0,0,194624,5911.9,696320,56546.5,86016,84855.8,3853,28.834,46,16.236,45.07 4:55 PM,24320,24960,0,6408.4,197184,116985.5,695424,55662.8,86016,85013.5,3873,29.072,48,16.737,45.809 4:56 PM,27584,26624,0,0,198848,13178.7,695872,56027.9,86016,85115,3891,29.302,50,17.238,46.54 4:57 PM,24768,25344,0,6120.2,201152,11617.5,699072,66807,86016,84833.5,3903,29.415,52,17.746,47.161 4:58 PM,31360,30144,0,0,201408,15841.7,695552,56110.8,86016,84941.2,3915,29.574,54,18.28,47.854 4:58 PM,26816,27328,0,0,203968,200718.2,695552,56148.9,86016,84772.1,3924,29.66,56,18.818,48.478 4:58 PM,24640,24192,0,0,205568,6781.7,694784,55459.3,86016,84862.6,3933,29.749,58,19.334,49.083 4:59 PM,25408,24768,0,0,206656,142158.9,695936,56542.1,86016,85030.8,3945,29.879,60,19.85,49.729 4:59 PM,22272,22784,0,0,207808,32725.9,698112,58714.1,86016,85028.4,3954,29.962,62,20.333,50.295 5:00 PM,24256,26752,20616.2,0,206464,0,698112,58714.1,86016,86015.3,3958,30.029,63,20.333,50.362 5:00 PM,27072,26752,0,0,206464,177035.1,696512,57149.9,86016,85023.8,3959,30.033,64,20.881,50.914 5:00 PM,23616,25024,11541.6,0,206848,86827.7,699072,68513,86016,85068.1,3972,30.17,66,21.406,51.577 5:00 PM,45376,44608,0,0,201280,5971.1,696832,56658.2,86016,84562.1,3979,30.261,68,21.976,52.237 5:01 PM,32960,32192,0,0,205056,0,699072,56332.7,86016,84866.3,3991,30.398,70,22.202,52.6 5:02 PM,28736,27968,0,0,207168,172703.6,696960,57376.4,86016,85041.3,4003,30.55,72,22.965,53.515 5:02 PM,58304,56640,0,0,200448,17691.4,699072,73691.8,86016,85065.8,4019,30.823,74,23.586,54.409 5:03 PM,45440,45568,0,0,205440,0,699072,76301.1,86016,86015.3,4028,30.927,76,23.875,54.801 5:03 PM,35328,35008,0,0,207744,0,699072,69190.2,86016,86016,4035,31.017,78,24.439,55.456 5:04 PM,37184,36288,0,0,208384,4697.6,695360,55963.9,86016,84995,4045,31.174,80,25.276,56.45 5:04 PM,33216,31744,0,22920.2,210112,0,695360,55963.9,86016,86016,4053,31.3,81,25.276,56.576 5:04 PM,33216,33984,0,0,211840,21490.1,699072,73818.2,86016,85126.7,4054,31.304,82,25.811,57.115 5:05 PM,30336,29696,0,0,216064,12973.1,695808,56419.4,86016,84650.2,4063,31.41,84,26.383,57.793 5:05 PM,29824,28928,0,0,218432,14631.5,695168,55755.8,86016,84752.6,4079,31.628,86,26.926,58.553 5:06 PM,28288,29696,21896.2,0,219648,0,695168,55755.8,86016,86015.7,4090,31.822,87,26.926,58.748 5:06 PM,30784,29696,0,0,219648,114035.2,699072,71706.3,86016,85063.2,4091,31.826,88,27.465,59.291 5:07 PM,33600,33984,0,6492.5,220544,12372.9,697600,58186.4,86016,84697.7,4105,32.044,90,27.974,60.018 5:08 PM,53120,55296,0,0,214080,0,699072,62305.5,86016,86015.1,4120,32.646,92,28.251,60.896 5:08 PM,45184,44800,0,0,217984,11395.4,695936,56523.3,86016,85284.8,4129,32.763,94,29.026,61.789 5:08 PM,39168,39744,0,4448,219648,0,695936,56523.3,86016,86015.5,4133,32.803,95,29.026,61.829 5:08 PM,39168,39168,0,0,220288,10799.8,695168,55806.7,86016,84689,4134,32.806,96,29.519,62.326 5:09 PM,33600,35264,0,0,221632,0,699072,77192.8,86016,86015.9,4143,32.939,97,29.788,62.726 5:09 PM,35776,35264,0,0,221632,53684.3,699072,73448.4,86016,84706.1,4143,32.945,98,30.05,62.994 5:09 PM,32384,33152,0,0,224256,0,699072,76427.6,86016,86015.9,4156,33.169,100,30.327,63.496 5:10 PM,32576,33600,0,0,227264,125912.5,699072,72837.7,86016,85068.7,4168,33.341,102,31.133,64.474 5:10 PM,32384,31424,0,0,229120,0,699072,75880.8,86016,86016,4177,33.501,104,31.412,64.913 5:11 PM,30144,29312,0,0,231104,0,698944,59546.9,86016,86015.6,4189,33.649,106,31.919,65.568 5:12 PM,33536,32448,0,0,229120,63917.4,699072,73943.8,86016,84703.4,4201,33.844,108,32.732,66.576 5:12 PM,30656,31360,0,7258.8,232320,86868.5,699072,63084.4,86016,85106.6,4209,33.968,110,33.295,67.262 5:13 PM,41152,42880,0,0,240064,125620.6,699072,73671.1,86016,84806.9,4240,34.663,112,33.886,68.549 5:14 PM,39680,41216,6888.2,0,257280,7079.4,699072,69241.7,86016,84850.1,4282,35.592,114,34.422,70.014 5:15 PM,40000,39232,0,0,252352,165424.9,698240,57297.2,86016,85007.1,4317,36.319,116,34.93,71.249 5:16 PM,48320,48512,0,7802.9,220672,0,698240,81401.4,86016,86015.3,4347,37.032,117,34.93,71.962 5:16 PM,43456,45696,12794.8,0,222656,83253.6,699072,60327,86016,84892.7,4350,37.053,118,35.458,72.511 5:17 PM,44672,7040,0,7016.4,248256,14476,696896,55393.3,86016,84955.8,4393,38.08,120,35.992,74.073 5:18 PM,32832,33728,0,0,252992,5223.4,696256,55701.8,86016,84759.6,4414,38.433,122,36.486,74.92 5:19 PM,32128,33216,0,0,254912,10469.2,696320,55884.7,86016,84952.8,4432,38.718,124,36.967,75.685 5:20 PM,31488,32512,0,0,259008,8660.1,695744,55503.6,86016,84847.6,4450,39.046,126,37.468,76.515 5:21 PM,30720,31616,0,0,260416,0,698112,58288.5,86016,86015.7,4468,39.355,128,37.706,77.061 5:22 PM,29376,28544,0,0,264000,4977.9,695296,55782.2,86016,85046.7,4483,39.598,130,38.462,78.06 5:23 PM,30208,29248,0,0,266688,63835.5,695936,56502.7,86016,85099.9,4497,39.829,132,38.988,78.817 5:24 PM,30848,29888,0,0,269696,16305.1,695168,55754.6,86016,84881.5,4511,40.065,134,39.557,79.622 5:24 PM,30848,29824,0,0,272128,190589.7,697344,57937.4,86016,85159,4523,40.253,136,40.071,80.324 5:25 PM,43328,25280,0,25224.2,259200,0,697344,59665.4,86016,86015.4,4533,40.662,137,40.071,80.732 5:25 PM,44352,44800,0,7132.5,257728,114736,697152,57231.9,86016,84855.8,4535,40.673,138,40.608,81.281 5:26 PM,57344,57536,6824.4,0,234432,43051.1,699072,56547.9,86016,84826.9,4554,41.42,140,41.189,82.609 5:27 PM,40384,39552,0,0,241472,9214.1,698048,56042.8,86016,85068.4,4569,41.654,142,41.733,83.387 5:28 PM,33856,34880,0,0,246144,142425.9,699072,72538.1,86016,85050.2,4584,41.858,144,42.29,84.148 5:29 PM,34624,35840,0,0,246912,0,699072,75336.9,86016,86015.9,4600,42.124,146,42.579,84.703 5:30 PM,30528,29696,0,0,251712,8659.2,695168,55628,86016,84960.3,4619,42.419,148,43.386,85.804 5:31 PM,54976,56896,0,0,235712,46460.7,699072,55692.1,86016,84808.4,4638,43.443,150,43.882,87.324 5:32 PM,34240,34432,0,21864.2,244608,0,699072,58492.1,86016,86015.9,4659,43.833,151,43.882,87.715 5:32 PM,34240,35776,0,0,245632,218408.9,699072,70700.8,86016,85191,4660,43.837,152,44.406,88.242 5:33 PM,38528,40320,0,0,248256,2285.5,695808,55692,86016,85211,4676,44.181,154,44.935,89.116 5:34 PM,32896,34176,0,0,252800,39141,696256,56017.4,86016,85089.1,4694,44.492,156,45.527,90.018 5:35 PM,30528,31744,0,0,257792,7705.7,696320,55393.1,86016,84869,4718,44.881,158,46.092,90.973 5:36 PM,31616,32640,0,0,259200,769.5,695552,55291,86016,84766.7,4736,45.171,160,46.649,91.82 5:38 PM,31296,32576,0,0,264320,8005.1,696512,55448.5,86016,85074.6,4766,45.689,162,47.198,92.887 5:46 PM,34048,6848,0,6848,282176,0,696512,99912.5,86016,86015.9,4873,47.811,163,47.198,95.009 5:46 PM,34048,35456,0,0,278592,3379.3,696576,55326.5,86016,84954.3,4874,47.814,164,47.796,95.61 5:54 PM,31488,30336,0,0,286144,237399.7,696768,55451.5,86016,85142.3,4987,49.961,166,48.324,98.285 6:02 PM,32192,30848,0,0,274368,5980.1,696640,55332.1,86016,85108.1,5103,52.314,168,48.916,101.23 6:09 PM,38144,64,0,0,276416,15814.6,697536,56164.9,86016,85325.8,5159,53.572,170,49.522,103.094 6:11 PM,34752,33536,0,0,275456,5206.4,697280,56571.9,86016,85075.4,5167,53.733,172,50.078,103.812
============================CSV data end ================================----- Original Message ----- From: "Jeffrey Janner" <jeffrey.jan...@polydyne.com>
To: "Tomcat Users List" <users@tomcat.apache.org> Sent: Friday, May 28, 2010 1:26 AM Subject: RE: tomcat memory question
-----Original Message----- From: Christopher Schultz [mailto:ch...@christopherschultz.net] Sent: Thursday, May 27, 2010 9:40 AM To: Tomcat Users List Subject: Re: tomcat memory question -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 塗, On 5/27/2010 4:51 AM, 塗 wrote: > there is a problem with my webapp. > > web operating environment: > tomcat5.5.27 + Apache/2.2.3 + jdk1.5.0_13 + Linux_x86_64 > > [below] is my manual configurations for tomcat JVM: > CATALINA_OPTS="-Xms1024M -Xmx1024M > -Dorg.apache.jasper.compiler.Parser.STRICT_QUOTE_ESCAPING=false" Are you using a 64-bit or 32-bit JVM? > When my webapp is started, I use the jvm's own tools(jstat) to trace the > garbage collections. Ok. > the Utilization rate of the PC capacity is always 100%. is it normal? What is "PC" (sorry, the jstat man page sucks)? What is the command you used to produce your jstat output?Well, PC is apparently Permanent Capacity in KB, and PU is the current Permanent Utilization (not to be confused with PermGen apparently). Taking his data a sticking it in a spreadsheet (to make it readable) shows that PC is increasing and keeping slightly ahead of PU. I'd say nothing to worry about unless PC is starting to reach PGCMX (which is? Try including the -gccapacity option). Looks like normal GC at work to me.> Firstly the 1 Full GC is occurrenced within 1 hour, > 5 hours later that took place within 1 hour 100 Full GC. > is it normal? Can you clarify this last statement? When did the first full GC take place? When did the second? When did the third? Are you saying that you get one full GC in one hour, then 5 hours for the second, then 100 full GCs all close together?The OPs original statement makes no sense in light of the data give. There is no Full GC count line in his data (though doc says there should be: http://java.sun.com/j2se/1.5.0/docs/tooldocs/share/jstat.html). The doc seems to imply that the GC times should be cumulative from start, so it looks like he's done some Full GC between each sample taken (about 7 secs/hr.) It would be really helpful if he had listed his jstat options.All the actual capacity/utilization numbers appear to be rising and falling over time in apparent relation to normal usage. The permanent util number doesn't seem to drop often, so he may have a memory leak. (I'd seek the opinion of someone more versed than me in reading jstat output though.)It would have been useful if he had a specific issue he was having and trying to resolve.That suggests to me that your webapp is allocating memory and never releasing it. This could be due to many reasons such as a memory leak (which ought to be fixed) or caching (which may be working as designed). Is your webapp performing well? GC activity doesn't necessarily mean that anything is wrong. - -chris -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.10 (MingW32) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEARECAAYFAkv+hFoACgkQ9CaO5/Lv0PBFkgCgvqoksV7PgaqGFOI5wCgXwaIa yKcAniKySqd3g8wd7paAoRBn0mWklSZY =RfE/ -----END PGP SIGNATURE----- --------------------------------------------------------------------- To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org******************************* NOTICE ********************************* This message is intended for the use of the individual or entity to which it is addressed and may contain information that is privileged, confidential, and exempt from disclosure under applicable law. If the reader of this message is not the intended recipient or the employee or agent responsible for delivering this message to the intended recipient, you are hereby notified that any dissemination, distribution, or copying of this communication is strictly prohibited. If you have received this communication in error, please notify us immediately by reply or by telephone (call us collect at 512-343-9100) and immediately delete this message and all its attachments.
gc.csv
Description: MS-Excel spreadsheet
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