<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">Peter, this must be a bug in the GC output as I know for sure I don't have the memory to run a 20GB heap.<div><br></div><div>Instead of 20950272K, it must mean 20950272K<b>b</b>.</div><div><br></div><div>This is on Java 1.5.0 on OS X Leopard.</div><div><br></div><div><div>java version "1.5.0_13"</div><div>Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0_13-b05-237)</div><div>Java HotSpot(TM) Server VM (build 1.5.0_13-119, mixed mode)</div><div><br></div><div><br></div><div>-Moazam</div><div><br></div></div><div><div><div>On Nov 4, 2008, at 4:52 PM, Peter B. Kessler wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div>Moazam Raja wrote:<br><blockquote type="cite">Hi all, I'm running a test and recording GC information on a Tomcat application and have noticed that even after a few days, there are no 'Full GC' markers. Am I reading the log incorrectly, or are the Full GCs getting logged elsewhere?<br></blockquote><blockquote type="cite">I'm using Java 1.5.0_13 on OS X with the following flags,<br></blockquote><blockquote type="cite"> -Xms=2048m -Xmx=2048m<br></blockquote><blockquote type="cite"> -server -XX:+UseConcMarkSweepGC<br></blockquote><blockquote type="cite"> -Xloggc:/var/tmp/GC.log<br></blockquote><blockquote type="cite"> -verbose:gc<br></blockquote><blockquote type="cite"> -XX:+PrintGCDetails<br></blockquote><blockquote type="cite"> -XX:+PrintHeapAtGC<br></blockquote><blockquote type="cite"> -XX:+PrintClassHistogram<br></blockquote><blockquote type="cite"> -XX:+PrintGCApplicationConcurrentTime<br></blockquote><blockquote type="cite">A sample of the output from my GC log:<br></blockquote><blockquote type="cite">Application time: 1.4105823 seconds<br></blockquote><blockquote type="cite">82558.187: [GC {Heap before gc invocations=111716:<br></blockquote><blockquote type="cite"> par new generation total 21184K, used 21120K [0x0000000107270000, 0x0000000108730000, 0x0000000108730000)<br></blockquote><blockquote type="cite"> eden space 21120K, 100% used [0x0000000107270000, 0x0000000108710000, 0x0000000108710000)<br></blockquote><blockquote type="cite"> from space 64K, 0% used [0x0000000108710000, 0x0000000108710000, 0x0000000108720000)<br></blockquote><blockquote type="cite"> to space 64K, 0% used [0x0000000108720000, 0x0000000108720000, 0x0000000108730000)<br></blockquote><blockquote type="cite"> concurrent mark-sweep generation total 20950272K, used 5483440K [0x0000000108730000, 0x0000000607270000, 0x0000000607270000)<br></blockquote><blockquote type="cite"> concurrent-mark-sweep perm gen total 39296K, used 23575K [0x0000000607270000, 0x00000006098d0000, 0x000000060c670000)<br></blockquote><blockquote type="cite">82558.187: [ParNew: 21120K->0K(21184K), 0.0669633 secs] 5504560K->5487545K(20971456K)Heap after gc invocations=111717:<br></blockquote><blockquote type="cite"> par new generation total 21184K, used 0K [0x0000000107270000, 0x0000000108730000, 0x0000000108730000)<br></blockquote><blockquote type="cite"> eden space 21120K, 0% used [0x0000000107270000, 0x0000000107270000, 0x0000000108710000)<br></blockquote><blockquote type="cite"> from space 64K, 0% used [0x0000000108720000, 0x0000000108720000, 0x0000000108730000)<br></blockquote><blockquote type="cite"> to space 64K, 0% used [0x0000000108710000, 0x0000000108710000, 0x0000000108720000)<br></blockquote><blockquote type="cite"> concurrent mark-sweep generation total 20950272K, used 5487545K [0x0000000108730000, 0x0000000607270000, 0x0000000607270000)<br></blockquote><blockquote type="cite"> concurrent-mark-sweep perm gen total 39296K, used 23575K [0x0000000607270000, 0x00000006098d0000, 0x000000060c670000)<br></blockquote><blockquote type="cite">}<br></blockquote><blockquote type="cite">, 0.0672098 secs]<br></blockquote><blockquote type="cite">...<br></blockquote><br>I don't think those are the command line arguments for the GC log you show. It looks from the PrintHeapAtGG output that your heap is 20GB, not the 2GB shown on the command line. 20MB in the "par new" generation, and the reast of the 20GB in the CMS generation.<br><br>It looks like you are using just over 5GB of CMS space, which would explain why you haven't seen an old generation collection yet.<br><br><span class="Apple-tab-span" style="white-space:pre"> </span><span class="Apple-tab-span" style="white-space:pre"> </span><span class="Apple-tab-span" style="white-space:pre"> </span>... peter<br></div></blockquote></div><br></div></body></html>