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239 discussions - 1,168 posts

  • Hi, We're using a time-series database to store and aggregate monitoring data from our systems, including GC behavior. I'm thinking of adding two metrics: * total allocation (in K per minute) * total ...
    Taras TielkesTaras Tielkes
    Apr 22, 2012 at 1:24 pm
    Apr 22, 2012 at 9:35 pm
  • Hi, Are there plans to port RFE 7068625 to Java 6? Thanks, -tt
    Taras TielkesTaras Tielkes
    Apr 20, 2012 at 12:46 pm
    Apr 23, 2012 at 12:18 am
  • Hi all I still see a lot of discussions around CMS. G1 is supposed to solve some of CMS's issues/limitations, namely fragmentation. I gave G1 a try about a year ago and it seemed not yet ready. Has ...
    Alex AisinzonAlex Aisinzon
    Apr 20, 2012 at 9:26 am
    Apr 20, 2012 at 10:05 am
  • hi all: I'm currently using jdk 6u26. I just enabled UseParallelOldGC, expecting that would enhance the full gc efficiency and decrease the mark-sweep time by using multiple-core. The JAVA_OPTS is as ...
    The 6th MonthThe 6th Month
    Apr 18, 2012 at 1:16 am
    Apr 20, 2012 at 4:20 pm
  • Hi, Till date I was using JRE 6u22 with following garbage collection parameters and the CMS cycle use to kick-in appropriately (when heap reaches 75%) -server -d64 -Xms2048m -Xmx2048m -javaagent ...
    Shivkumar ChelwaShivkumar Chelwa
    Apr 17, 2012 at 8:08 am
    Apr 17, 2012 at 1:52 pm
  • Hi there, We are measuring certain aspects of our algorithm with a test suite which attempts to run close to the physical heap's maximum size. We do it by doing a form of binary search based on the ...
    Dawid WeissDawid Weiss
    Apr 11, 2012 at 7:24 am
    Apr 15, 2012 at 1:12 am
  • I ran performance tests on one of our apps and saw the following error message in the GC logs: Java HotSpot(TM) 64-Bit Server VM warning: CodeCache is full. Compiler has been disabled. Java ...
    Alex AisinzonAlex Aisinzon
    Apr 9, 2012 at 11:37 am
    Apr 20, 2012 at 10:34 am
  • Hi all, This is probably the wrong forum to ask however. I am writing a simple C program that can take hprof heap dumps (the ones from OutOfMemoryError) and extract out a few interesting statistics ...
    Greg BowyerGreg Bowyer
    Mar 31, 2012 at 8:26 pm
    Mar 31, 2012 at 8:26 pm
  • The following GC trace was obtained soon after the JVM was started (a lot of transient objects are generated as a part of the start up and hence a lot of minor GCs). ( Xms = Xmx = 2G, NewGen = 1/3 of ...
    Kobe BryantKobe Bryant
    Mar 30, 2012 at 1:32 pm
    Mar 30, 2012 at 7:14 pm
  • i am using jdk1.6. I configureg Xmx = 2G, Xms= 2G, NewSize = MaxNewSize = 660m I enable verbose gc. I see this which I am not understanding: PSYoungGen total 608256K, used 32440K eden space 540672K, ...
    Kobe BryantKobe Bryant
    Mar 28, 2012 at 12:33 pm
    Mar 28, 2012 at 2:26 pm
  • for 64bit JVM, if heap usage is less than 4GB, it should enable this option. it can reduce memory usage and performance(for cpu cache). What if the JVM use large memory? ...
    Li LiLi Li
    Mar 15, 2012 at 12:19 am
    Mar 15, 2012 at 8:00 am
  • Hi,All: I've recently encountered a memory usage surge of JVM, the JVM version is jdk6, 6u26. What we see from the top command is as below: top - 20:12:17 up 112 days, 8:26, 1 user, load average ...
    The 6th MonthThe 6th Month
    Mar 12, 2012 at 5:49 am
    Mar 12, 2012 at 5:49 am
  • hi,hi: I've just come across a weird situation where JVM ate swap space occasionally even when there's free memory available. Has anyone got any idea about how to diagnose such problem? The output of ...
    The 6th MonthThe 6th Month
    Mar 2, 2012 at 6:47 am
    Mar 5, 2012 at 1:44 am
  • ----------------------------------------------------------------------- Krystal Mok wants to stay in better touch using some of Google's coolest new products. If you already have Gmail or Google ...
    Krystal MokKrystal Mok
    Mar 1, 2012 at 9:18 pm
    Mar 1, 2012 at 9:18 pm
  • Turning off maximal compaction seems to have worked to get rid of the outlier times, just as we had conjectured. (Charlie may want to add that to the next edition of his book ;-) We'll see how well ...
    Srinivas RamakrishnaSrinivas Ramakrishna
    Mar 1, 2012 at 1:37 pm
    Mar 2, 2012 at 2:54 pm
  • I have an application running in a machine with 6 GB memory. And the java program is allocated to use 4000M heap by -Xmx4000m and -Xms4000m. But we found it use swap memory and system get slower ...
    Li LiLi Li
    Mar 1, 2012 at 3:13 am
    Mar 2, 2012 at 10:41 am
  • Hi all, I have seen Class.forName() causes the tenured generation got filled with custom ClassLoader objects. I suspect something JVM done internally will move the ClassLoader objects to tenured ...
    Feb 26, 2012 at 8:50 pm
    Feb 26, 2012 at 9:29 pm
  • Hi Jo{h}n, all -- Is there some way i can get at the dense prefix value used for ParOld in each (major) collection? I couldn't find an obvious product flag for eliciting that info, but wondered if ...
    Srinivas RamakrishnaSrinivas Ramakrishna
    Feb 17, 2012 at 9:46 am
    Feb 20, 2012 at 9:34 am
  • I've written a fairly small program that runs in 256 MB -- this program will load several large pictures, which are being "cached" using SoftReferences. The more of these pictures get loaded, the ...
    John HendrikxJohn Hendrikx
    Feb 17, 2012 at 8:54 am
    Feb 18, 2012 at 3:21 pm
  • Your question would be better answered by someone on the hotstpot-gc-use list, cc'ed. You don't mention which version of the JDK you're using, but you should be using the latest update of JDK 7, ...
    Paul HohenseePaul Hohensee
    Feb 17, 2012 at 8:38 am
    Feb 17, 2012 at 9:36 am
  • hi all, I found our application's perm generation size is continuously increasing and will reach 100%(we limit maxPermSize to 256MB) and perform a full gc(which will pause for 10s).after gc, perm ...
    Li LiLi Li
    Feb 16, 2012 at 2:55 am
    Feb 20, 2012 at 6:37 am
  • Hello Guys, I tried to write my own monitoring tool to create dynamically views based on command line parameters. If someone needs the code for verification you find the source here ...
    Philipp StieglerPhilipp Stiegler
    Feb 2, 2012 at 11:55 am
    Feb 3, 2012 at 1:40 pm
  • Hi Team, For last couple of weeks, while monitoring production logs, we are seeing following 2 scenarios- 2012-01-30T09:45:57.783+0530: 211563.940: [GC 211563.941: [ParNew: 1695683K- ...
    Pravah wordpressPravah wordpress
    Feb 2, 2012 at 9:30 am
    Feb 10, 2012 at 4:51 am
  • Hi, How do you enable heap verification? Is there a place where I can read more about what it does? -- Venlig hilsen / Kind regards, Christian Vest Hansen. An HTML attachment was scrubbed... URL ...
    Christian Vest HansenChristian Vest Hansen
    Jan 25, 2012 at 1:37 am
    Jan 25, 2012 at 1:37 am
  • Hi all, working through my GC issues I have found that the fix for CMS weak references is making my GC far more predictable However I occasionally find that sometimes I see a ParNew collection of 1 ...
    Greg BowyerGreg Bowyer
    Jan 23, 2012 at 2:39 pm
    Jan 23, 2012 at 5:45 pm
  • Hi all I have an application that is solr/lucene running on JDK 1.6 / 1.7 with CMS, 9Gb heap. The only unusual options here are DisableExplictGC and UseCompressedOops (which I do not think are the ...
    Greg BowyerGreg Bowyer
    Jan 19, 2012 at 1:37 pm
    Jan 20, 2012 at 10:48 am
  • Hi all, We have a backend type of application which primary purpose is to cache user specific graphs of objects. The graphs are relatively small in size however the rate at which they can change ...
    Bartek MarkockiBartek Markocki
    Jan 12, 2012 at 5:56 am
    Jan 12, 2012 at 5:56 am
  • hi all I have an application that generating many large objects and then discard them. I found that full gc can free memory from 70% to 40%. I want to let this objects in young generation longer. I ...
    Li LiLi Li
    Jan 10, 2012 at 1:31 am
    Jan 12, 2012 at 11:11 am
  • Hi everybody, I am using CMS (with ParNew) gc and have very long ( 6 seconds) young gc pauses. As you can see in the log below the old-gen-heap consists of one large block, the new Size has 256m, it ...
    Florian BinderFlorian Binder
    Jan 9, 2012 at 3:08 am
    Jan 11, 2012 at 1:45 am
  • Hello GC team, I have question regarding ParNew collection. As in logs below, the GC is taking only 0.04 sec but application was stopped for 1.71 sec. What could possibly cause this? Please advise ...
    Darji, KinnariDarji, Kinnari
    Jan 3, 2012 at 1:36 pm
    Jan 10, 2012 at 8:24 am
  • Thanks for the answer, is there any chance you can also help with my other question? Is there a way with as with cms to control the "occupancy"? Thanks, Guy more -- Regards, Guy Korland An HTML ...
    Guy KorlandGuy Korland
    Dec 28, 2011 at 1:17 pm
    Dec 30, 2011 at 1:26 pm
  • Is there a way to set the G1 Occupancy? We noticed it doesn't really kick in before the JVM is pretty full. Thanks, Guy An HTML attachment was scrubbed... URL ...
    Guy KorlandGuy Korland
    Dec 27, 2011 at 1:27 pm
    Dec 27, 2011 at 1:27 pm
  • Hi, I hope this is the right forum for this. It seems like no matter how small we set the young generation, it take more than 20ms. Is there a way turn off generational GC, especially in CMS? Thanks, ...
    Guy KorlandGuy Korland
    Dec 27, 2011 at 1:20 pm
    Dec 27, 2011 at 2:06 pm
  • Hi, We're running an application with the CMS/ParNew collectors that is experiencing occasional promotion failures. Environment is Linux 2.6.18 (x64), JVM is 1.6.0_29 in server mode. I've listed the ...
    Taras TielkesTaras Tielkes
    Dec 27, 2011 at 5:07 am
    Apr 17, 2012 at 4:38 am
  • hi all, I want to allocate and free memory as c/c++ language and I found the Unsafe in hotspot vm. I know the danger of using this class. But I still want to try it. allocateMemory and freeMemory are ...
    Li LiLi Li
    Dec 23, 2011 at 3:14 am
    Dec 23, 2011 at 9:46 am
  • Hello all, I want to ask all of you on question ! I am normally working with SunJDK for my application (Java(TM) SE Runtime Environment (build 1.6.0_15-b03)) , but now I want to migrate the openJDK ( ...
    Toni Menendez LopezToni Menendez Lopez
    Dec 12, 2011 at 1:00 pm
    Dec 12, 2011 at 1:00 pm
  • Hi all, I was looking for a short test to reproduce the vm-crash when using ObjectAlignment but found an other combination of options which result in a vm-crash ;-) I have attached the java-source ...
    Florian BinderFlorian Binder
    Dec 6, 2011 at 12:23 pm
    Dec 6, 2011 at 12:23 pm
  • Florian, inline. I assume you know when the data will be dropped and reinitialized, right? Can you do a Full GC (with System.gc()) after you re-initialize the heap. This typically helps a lot with ...
    Tony PrintezisTony Printezis
    Dec 5, 2011 at 9:21 am
    Dec 12, 2011 at 6:45 am
  • Hi everybody, I have a java application with 20gb (large-table) memory and using the g1 garbage collector. The application calculates the whole time with 10 threads some ratios (high cpu load). This ...
    Florian BinderFlorian Binder
    Nov 28, 2011 at 11:18 am
    Nov 30, 2011 at 12:35 am
  • hi everybody, I read an article today about Azul's Zing JVM. It is said that this jvm is pauseless. In my application, our machine is about 48GB and about 25GB memory is given to jvm(by -Xmx). But it ...
    Li LiLi Li
    Nov 28, 2011 at 1:25 am
    Nov 28, 2011 at 6:54 am
  • This is from an old thread in 2011 April but we're still seeing the same problem with (nio) Socket instances not getting collecting by CMS. Opened ...
    Koji NoguchiKoji Noguchi
    Nov 22, 2011 at 1:06 pm
    Nov 30, 2011 at 4:03 pm
  • Hi, Is there a way to get printed a survivor space class histogram on every minor collection run? Tony once provided us a special jdk build containing this feature but it got never integrated as a ...
    Michal FrajtMichal Frajt
    Nov 16, 2011 at 3:45 pm
    Nov 17, 2011 at 8:53 am
  • dear mailing list, we try to achieve low latencies despite using a huge heap (10G) and many logical cores (64). VM is 1.7u1. Ideally, we would let GC ergonomics decide what is best, giving only a low ...
    Ralf HelbingRalf Helbing
    Nov 16, 2011 at 7:02 am
    Nov 16, 2011 at 7:22 am
  • I am posting this to hotspot-gc-use, but the idea is that it also post to -dev (but given how the lists are arranged, I am posting directly to the one and not the other to avoid double copies to ...
    Srinivas RamakrishnaSrinivas Ramakrishna
    Nov 11, 2011 at 2:31 pm
    Nov 14, 2011 at 2:22 pm
  • Hi, I recently encountered an interesting GC issue with a Tomcat application. I came up with a simple repro scenario which I posted to StackOverflow ...
    Martin Hare RobertsonMartin Hare Robertson
    Nov 5, 2011 at 3:29 pm
    Nov 8, 2011 at 10:20 am
  • Hi, We have an application running with a 6GB heap (complete parameters below). Mostly it has a fairly low turnover of memory use, but on occasion, it will come under some pressure as it reloads a ...
    Jon BrightJon Bright
    Oct 31, 2011 at 6:06 am
    Nov 1, 2011 at 6:50 am
  • Lawrence Chow will be out of the office on 10/02/11 through 10/06/11 Lawrence will return to the office on Friday, 10/07/11. Please contact Matt.Miller at oracle.com, Terry.Statt at oracle.com, or ...
    Lawrence ChowLawrence Chow
    Oct 5, 2011 at 12:03 pm
    Oct 5, 2011 at 12:03 pm
  • Hello, ? I am intermittently getting the below Out of Memory error for a Java application running on Windows 2003 with 4 GB RAM. ? jvm 2??? | 2011/10/03 02:08:00 | # jvm 2??? | 2011/10/03 02:08:00 | ...
    Anjul Narain VarmaAnjul Narain Varma
    Oct 4, 2011 at 11:35 am
    Oct 28, 2011 at 1:22 am
  • Hi Srini -- As I indicated, if you cannot upgrade easily to test if the issue is fixed, you should probably engage JVM support to get to a proper diagnosis of the issue affecting your production ...
    Y. S. RamakrishnaY. S. Ramakrishna
    Sep 29, 2011 at 5:54 pm
    Sep 30, 2011 at 10:55 am
  • Hey list, we used to use CMS for our java server. Our memory activity is very high, we use 4 CMS threads, and set initial fraction to 1 to aggressively collect old gen memory. The hardware we use has ...
    Junni FanJunni Fan
    Sep 25, 2011 at 9:07 am
    Sep 25, 2011 at 9:08 am
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