StackOverflow2013

Note that there are some explanatory texts on larger screens.

plurals

POWhat causes the G1 garbage collector in Java 7 to abort its concurrent-mark phase?
text
Body
copied!<p>I've noticed occasional full GC's in my application using the G1 garbage collector, and am trying to figure out why they happen. </p> <p>The cycle from one region-scan-start to the next is excerpted below. At 61807.406, a full GC is logged, followed by an entry for concurrent-mark-abort. What I want to know is why the GC felt the need to do a full, stop-the-world, garbage collection and how I can avoid it. </p> <p>Note that <a href="http://mail.openjdk.java.net/pipermail/hotspot-gc-use/2011-September/000917.html">this question</a> appears to have been asked before on the OpenJDK mailing list, with no responses.</p> <p>I've trimmed the details of the young GCs for brevity, but I can post the full chunk somewhere if needed.</p> <pre><code>61805.878: [GC concurrent-root-region-scan-start] 61805.882: [GC concurrent-root-region-scan-end, 0.0033586] 61805.882: [GC concurrent-mark-start] 61806.133: [GC pause (young), 0.02836202 secs] [Eden: 498M(498M)->0B(478M) Survivors: 14M->34M Heap: 3025M(4096M)->2548M(4096M)] [Times: user=0.19 sys=0.00, real=0.03 secs] 61806.426: [GC pause (young), 0.02766222 secs] [Eden: 478M(478M)->0B(480M) Survivors: 34M->32M Heap: 3050M(4096M)->2576M(4096M)] [Times: user=0.19 sys=0.00, real=0.03 secs] 61806.717: [GC pause (young), 0.02214895 secs] [Eden: 480M(480M)->0B(502M) Survivors: 32M->10M Heap: 3056M(4096M)->2571M(4096M)] [Times: user=0.09 sys=0.00, real=0.02 secs] 61807.000: [GC pause (young), 0.01899188 secs] [Eden: 502M(502M)->0B(502M) Survivors: 10M->10M Heap: 3074M(4096M)->2573M(4096M)] [Times: user=0.09 sys=0.00, real=0.02 secs] 61807.201: [GC pause (young), 0.02619259 secs] [Eden: 162M(502M)->0B(500M) Survivors: 10M->12M Heap: 3036M(4096M)->2876M(4096M)] [Times: user=0.11 sys=0.00, real=0.03 secs] 61807.283: [GC pause (young), 0.02068515 secs] [Eden: 102M(500M)->0B(500M) Survivors: 12M->12M Heap: 3058M(4096M)->2957M(4096M)] [Times: user=0.09 sys=0.00, real=0.02 secs] 61807.350: [GC pause (young), 0.01606520 secs] [Eden: 52M(500M)->0B(498M) Survivors: 12M->14M Heap: 3020M(4096M)->2969M(4096M)] [Times: user=0.11 sys=0.00, real=0.02 secs] 61807.389: [GC pause (young), 0.01573865 secs] [Eden: 42M(498M)->0B(500M) Survivors: 14M->12M Heap: 3021M(4096M)->2978M(4096M)] [Times: user=0.09 sys=0.00, real=0.02 secs] 61807.406: [Full GC 2978M->2498M(4096M), 4.8896638 secs] [Times: user=6.37 sys=0.08, real=4.89 secs] 61812.296: [GC concurrent-mark-abort] 61812.542: [GC pause (young), 0.01526403 secs] [Eden: 512M(500M)->0B(510M) Survivors: 0B->2048K Heap: 3018M(4096M)->2506M(4096M)] [Times: user=0.09 sys=0.00, real=0.02 secs] 61812.793: [GC pause (young) (initial-mark), 0.01391544 secs] [Eden: 510M(510M)->0B(508M) Survivors: 2048K->4096K Heap: 3016M(4096M)->2508M(4096M)] [Times: user=0.09 sys=0.00, real=0.01 secs] 61812.807: [GC concurrent-root-region-scan-start] </code></pre> <p>This is using the Java Hotspot 1.7.0_7 release, with the following interesting settings:</p> <pre><code>-XX:PermSize=128m -XX:MaxPermSize=128m -XX:NewSize=512m -XX:MaxNewSize=512m -Xms4096m -Xmx4096m -XX:+UnlockDiagnosticVMOptions -XX:+UnsyncloadClass -XX:+UseTLAB -XX:+UseG1GC -XX:SurvivorRatio=10 -Xloggc:./workspace/gc.log -verbose:gc -XX:+PrintGC -XX:+PrintGCTimeStamps -XX:+PrintGCDetails </code></pre>

Querying!

Guidance

An individual column

Larger individual text columns get their own page to allow for proper reading.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload