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Mark Hanson closed GEODE-2035. ------------------------------ Transition from Resolved to Closed for Apache Geode 1.11.0 RC4 release. > document how to use G1GC with geode > ----------------------------------- > > Key: GEODE-2035 > URL: https://issues.apache.org/jira/browse/GEODE-2035 > Project: Geode > Issue Type: Task > Components: docs > Reporter: Darrel Schneider > Assignee: Alberto Bustamante Reyes > Priority: Major > Labels: pull-request-available > Fix For: 1.11.0 > > Time Spent: 40m > Remaining Estimate: 0h > > The geode docs should describe how to configure G1GC for geode. > One issue is that if you use "gfsh start server --max-heap=SIZE" then it will > automatically configure CMS which does not work with G1GC. > So instead of using the "--max-heap" option we should tell them to use > "--J-XmxSIZE". > To configure G1GC use "--J-XX:+UseG1GC". > If you find the geode resource manager does not detect crossing the eviction > or critical threshold quickly enough then try using this option to make it > more responsive: "--J-XX:MaxGCPauseMillis=VALUE" where VALUE should be a > number less than 200 (which is the current G1GC default). We have done some > limited testing with this value set to 1 and it does make the resource > manager more responsive when combined with G1GC but it also increases the > amount of time spent in gc. > We also noticed that if the primary heap objects you allocate are large then > G1GC can cause the JVM to report out of heap memory when it has only used 50 > percent of the heap. We saw this with tests in which all the geode region > values were larger than 50 percent of the G1 region size. Oracle calls these > "humongous" objects. The default G1 region size is 1m. You can increase it up > to 32m (it is always a power of 2) by using this: > "--J-XX:G1HeapRegionSize=32m". If you are using large values and want to use > G1GC without increasing its RegionSize (or if you large values are bigger > than 16m) then you could make your geode regions that will contain the large > values off-heap. But even if you do that the large off-heap values will > allocate temporary large heap values that G1GC will treat as humongous > allocations even though they will be short lived. So consider using CMS if > most of you values will result in humongous allocations. -- This message was sent by Atlassian Jira (v8.3.4#803005)