Hello Thomas pon, 21. kol 2017. u 18:42 Thomas Schatzl <thomas.scha...@oracle.com> napisao je:
> > need you to confirm. Given region size of 8M and default G1 settings: > > * max number of PRT instances is 2^12 for each HR > > Where did you get the 2^12 from? > A bit simplified calculation of OtherRegionsTable::_max_fine_entries: _max_fine_entries = G1RSetRegionEntries = G1RSetRegionEntriesBase * (region_size_log_mb + 1) where: G1RSetRegionEntriesBase = 256 region_size_log_mb ... is 3, not 23. Ok, I made a mistake here. > * PRT size is 64MB > > Not completely following, where from do you understand that max prt > size is 64MB? > > 8M region size implies a 2k PRT (bitmap) size (one bit per 512 bytes) > Ah yes, my bed. It made several miscalculations also here. > Do only Young HR get a OtherRegionsTable? > > All regions get them. But there are no PRTs from young regions to old > regions. Humongous continues regions don't have any remembered set. > So there is only old-to-young, for each young? > Where can I find the number of regions per generation? I cannot spot > > it in GC logs. > > -Xlog:gc+heap=info gives you the following kind of output: > > Great. Thanks! Since e2 is slightly more memory efficient, it might be worth trying to > bump G1RSetSparseRegionEntries. > You don't remember, but we've gone through this some months ago. It did help indeed. Thanks again. If you think all what I explained above is gibberish to you, and > you are still interested, I can try to explain it a bit better :) > No, I actually understood everything, and have gone through all this in the code already.
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