On Monday, June 5, 2017 at 9:47:56 PM UTC+3, Kirk Pepperdine wrote: > > > On Jun 5, 2017, at 3:58 PM, Alexandr Nikitin <[email protected] > <javascript:>> wrote: > > Gil, Kirk, Thank you for the great and thorough explanation! It is an > awesome read! Almost everything fell into place. > > Indeed, Gil is right about the application pattern change. It's a > high-load API. There's a background thread that changes an internal state. > The state is ~3.5G and requires some similar amount of memory to build > itself. It happens in one background thread with lower priority. The change > doesn't happen often, once per hour or so. > > The G1 is new for me and I couldn't intuitively understand why it reacts > to the allocation pattern change like that. > > > All collectors in the JVM will react in a similar way. I’ve just spent 2 > hours with a client explaining to them that in their case GC wasn’t at > fault. It was simply shouting very loudly that something bad was happening > in the application that needed to be investigated. >
All collectors in the *HotSpot* JVM (Oracle or OpenJDK) will react in a similar way. All collectors in the Zing JVM (we only have one) won't. It takes a lot more than a few GB of promotion and a few GB/sec of allocation rate to make the C4 collector lose it's temper and complain that the programmer is doing it wrong ;-). > > There's the main allocation/ collection pattern that lasts for hours. And > it needs just one background low priority thread (which allocates less > memory than worker threads) to change it :) That region number change leads > to more copying and promotions and longer pauses as a consequence (it > changes max age threshold to 1 and happens more often) > > And the actual bottom line is very simple: You need a concurrent newgen to >> handle this workload, with these phase changes, without any of those >> "hiccups". We can discuss that in other posts if you want ;-). >> > > Do you mean Azul Zing by that? > > > Of course he does :-) > > And he’s not wrong. > > — Kirk > > PS, Gil, I’ll collect my commission on this lead once you close it. ;-) > -- You received this message because you are subscribed to the Google Groups "mechanical-sympathy" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
