On Tuesday, January 29, 2013 7:49:18 PM UTC-8, Bik Dhaliwal wrote: > > > Out group at my company is considering using the Zing JVM from Azul, > it promises zero GC pauses and in certain cases can vastly increase > performance and lower latency. > > I was wondering has had any experience dealing with this product and the > company. >
I'm obviously biased (I'm Azul's CTO), but I just wanted to correct the notion that we promise "zero GC pauses" in the above. I don't like promising "Zero GC pause" notion. What we do is bring pause times down to well below OS scheduling noise. While we completely decimate GC compared to there JVMs (by 100x-1000x factors at times), technically there are still 4 pauses per GC cycle. Those pauses are VERY short (as in milliseconds or less), and mostly deal with phase-shifting the collectors. Specifically, unlike other collectors and JVMs, Zing's pauses do not do any of the actual bulk GC work items like marking, copying or compacting, weak/soft/phantom/final ref processing, etc. All that work happens concurrently and outside of pauses and safepoints, making Zing's pause behavior not just super-short, but also independent of things like heap size, shape, and allocation rate. To use a picture instead of words, below is a sample graph showing all pauses (both GC and other safepoints like deoptimazation) from a busy multi-hour run of a heavy e-commerce workload at an actual (anonymized) customer [the longest pause seen in this case is around 5msec]. This same workload shows regular multi-second oldgen pauses and tens to hundreds of msec of newgen pauses on "well tuned" Oracle and OpenJDK JVMs. For Zing, most of the "longer" (above 1-2 msec) stuff has to do with scheduling noise and cpu contention. In finely tuned low latency environment we see stuff that goes well below that. <https://lh5.googleusercontent.com/-GIGWJ1iUBI4/UQ3W8tvN_vI/AAAAAAAAADY/KgxbevgNDak/s1600/PastedGraphic-3.a.png> -- You received this message because you are subscribed to the Google Groups "Java Posse" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/javaposse?hl=en. For more options, visit https://groups.google.com/groups/opt_out.
