> On Jun 5, 2017, at 9:02 PM, Gil Tene <[email protected]> wrote: > > > > 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 ;-).
Not an allocation issue.. more of workload backup.. not sure even C4 would react to this very well ;-) Regards, Kirk > > >> 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] > <mailto:[email protected]>. > For more options, visit https://groups.google.com/d/optout > <https://groups.google.com/d/optout>. -- 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.
