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I noticed that each young garbage collection with java 7 takes on average 10 more milliseconds than with java 6. I'm using 1.6.0_31 and 1.7.0_21. The configuration hasn't changed, neither has the hardware, JVM arguments are:
-server -XX:+DisableExplicitGC -XX:+UseConcMarkSweepGC -XX:+UseParNewGC -XX:+TieredCompilation -XX:+AggressiveOpts -Xms1g -Xmx1g -XX:MaxNewSize=256m -XX:NewSize=256m
S0C S1C S0U S1U EC EU OC OU PC PU YGC YGCT FGC FGCT GCT 26176.0 26176.0 3531.6 0.0 209792.0 21648.8 786432.0 86777.6 49472.0 49350.1 82 1.830 0 0.000 1.
S0C S1C S0U S1U EC EU OC OU PC PU YGC YGCT FGC FGCT GCT 26176.0 26176.0 0.0 1210.5 209792.0 95873.4 786432.0 65327.1 35968.0 35891.2 83 0.620 0 0.000 0.620
I also looked at each individual times, and with java 6, each YGC takes ~10ms vs java 7 is 20ms. Did something change between version 6 and 7 that could explain this behavior?
EDIT: I noticed that java 7 runs in 64 bits mode, whereas java 6 use a 32 bits JVM, could that explain the difference?
Thanks
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High Object Creation Rate A high garbage collection rate will increase the GC pause time as well. Thus, optimizing the application to create fewer objects is THE EFFECTIVE strategy to reduce long GC pauses. This might be a time-consuming exercise, but it is 100% worth doing.
Shenandoah GC and ZGC perform significantly better than G1GC in terms of latency, average pause time, maxi- mum pause time, and total accumulated stop-the-world time, for all evaluated applications in the study when the right tunings are applied. It is possible to achieve more than 80% improvement on latency values.
Z Garbage Collector (ZGC) ZGC is a low-latency garbage collector that works well with very large (multi-terabyte) heaps. Like G1, ZGC works concurrently with the application. ZGC is concurrent, single-generation, region-based, NUMA-aware, and compacting.
Default -XX:NewRatio for Java 6 is 8 but for the Java 7 it is 2. so in java 6 the size of young generation is less than java 7 hence the difference i feel.
Because time collecting the garbage from a city is directly proportional to how large the city is. if city size increases hence the time.
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