diff -r 5b5747ed8f34 -r 0a4829e4ad6b src/java.base/share/man/java.1 --- a/src/java.base/share/man/java.1 Mon Jul 22 15:54:25 2019 -0700 +++ b/src/java.base/share/man/java.1 Tue Jul 23 11:30:31 2019 -0700 @@ -1868,17 +1868,21 @@ .TP .B \f[CB]\-XX:\-UseCompressedOops\f[R] Disables the use of compressed pointers. -By default, this option is enabled, and compressed pointers are used -when Java heap sizes are less than 32 GB. -When this option is enabled, object references are represented as +By default, this option is enabled, and compressed pointers are used. +This will automatically limit the maximum ergonomically determined Java +heap size to the maximum amount of memory that can be covered by +compressed pointers. +By default this range is 32 GB. +.RS +.PP +With compressed oops enabled, object references are represented as 32\-bit offsets instead of 64\-bit pointers, which typically increases -performance when running the application with Java heap sizes of less -than 32 GB. +performance when running the application with Java heap sizes smaller +than the compressed oops pointer range. This option works only for 64\-bit JVMs. -.RS -.PP -It\[aq]s also possible to use compressed pointers when Java heap sizes -are greater than 32 GB. +.PP +It\[aq]s possible to use compressed pointers with Java heap sizes +greater than 32 GB. See the \f[CB]\-XX:ObjectAlignmentInBytes\f[R] option. .RE .TP @@ -3213,6 +3217,22 @@ \f[CB]\-XX:NewSize\f[R] option. .RE .TP +.B \f[CB]\-XX:InitialRAMPercentage=\f[R]\f[I]percent\f[R] +Sets the initial amount of memory that the JVM will use for the Java +heap before applying ergonomics heuristics as a percentage of the +maximum amount determined as described in the \f[CB]\-XX:MaxRAM\f[R] +option. +The default value is 1.5625 percent. +.RS +.PP +The following example shows how to set the percentage of the initial +amount of memory used for the Java heap: +.RS +.PP +\f[CB]\-XX:InitialRAMPercentage=5\f[R] +.RE +.RE +.TP .B \f[CB]\-XX:InitialSurvivorRatio=\f[R]\f[I]ratio\f[R] Sets the initial survivor space ratio used by the throughput garbage collector (which is enabled by the \f[CB]\-XX:+UseParallelGC\f[R] and/or @@ -3371,6 +3391,72 @@ .RS .RE .TP +.B \f[CB]\-XX:MaxRAM=\f[R]\f[I]size\f[R] +Sets the maximum amount of memory that the JVM may use for the Java heap +before applying ergonomics heuristics. +The default value is the maximum amount of available memory to the JVM +process or 128 GB, whichever is lower. +.RS +.PP +The maximum amount of available memory to the JVM process is the minimum +of the machine\[aq]s physical memory and any constraints set by the +environment (e.g. +container). +.PP +Specifying this option disables automatic use of compressed oops if the +combined result of this and other options influencing the maximum amount +of memory is larger than the range of memory addressable by compressed +oops. +See \f[CB]\-XX:UseCompressedOops\f[R] for further information about +compressed oops. +.PP +The following example shows how to set the maximum amount of available +memory for sizing the Java heap to 2 GB: +.RS +.PP +\f[CB]\-XX:MaxRAM=2G\f[R] +.RE +.RE +.TP +.B \f[CB]\-XX:MaxRAMPercentage=\f[R]\f[I]percent\f[R] +Sets the maximum amount of memory that the JVM may use for the Java heap +before applying ergonomics heuristics as a percentage of the maximum +amount determined as described in the \f[CB]\-XX:MaxRAM\f[R] option. +The default value is 25 percent. +.RS +.PP +Specifying this option disables automatic use of compressed oops if the +combined result of this and other options influencing the maximum amount +of memory is larger than the range of memory addressable by compressed +oops. +See \f[CB]\-XX:UseCompressedOops\f[R] for further information about +compressed oops. +.PP +The following example shows how to set the percentage of the maximum +amount of memory used for the Java heap: +.RS +.PP +\f[CB]\-XX:MaxRAMPercentage=75\f[R] +.RE +.RE +.TP +.B \f[CB]\-XX:MinRAMPercentage=\f[R]\f[I]percent\f[R] +Sets the maximum amount of memory that the JVM may use for the Java heap +before applying ergonomics heuristics as a percentage of the maximum +amount determined as described in the \f[CB]\-XX:MaxRAM\f[R] option for +small heaps. +A small heap is a heap of approximately 125 MB. +The default value is 50 percent. +.RS +.PP +The following example shows how to set the percentage of the maximum +amount of memory used for the Java heap for small heaps: +.RS +.PP +\f[CB]\-XX:MinRAMPercentage=75\f[R] +.RE +.RE +.TP .B \f[CB]\-XX:MaxTenuringThreshold=\f[R]\f[I]threshold\f[R] Sets the maximum tenuring threshold for use in adaptive GC sizing. The largest value is 15. @@ -3802,6 +3888,45 @@ .RS .RE .TP +.B \f[CB]\-XX:InitialRAMFraction=\f[R]\f[I]ratio\f[R] +Sets the initial amount of memory that the JVM may use for the Java heap +before applying ergonomics heuristics as a ratio of the maximum amount +determined as described in the \f[CB]\-XX:MaxRAM\f[R] option. +The default value is 64. +.RS +.PP +Use the option \f[CB]\-XX:InitialRAMPercentage\f[R] instead. +.RE +.TP +.B \f[CB]\-XX:MaxRAMFraction=\f[R]\f[I]ratio\f[R] +Sets the maximum amount of memory that the JVM may use for the Java heap +before applying ergonomics heuristics as a fraction of the maximum +amount determined as described in the \f[CB]\-XX:MaxRAM\f[R] option. +The default value is 4. +.RS +.PP +Specifying this option disables automatic use of compressed oops if the +combined result of this and other options influencing the maximum amount +of memory is larger than the range of memory addressable by compressed +oops. +See \f[CB]\-XX:UseCompressedOops\f[R] for further information about +compressed oops. +.PP +Use the option \f[CB]\-XX:MaxRAMPercentage\f[R] instead. +.RE +.TP +.B \f[CB]\-XX:MinRAMFraction=\f[R]\f[I]ratio\f[R] +Sets the maximum amount of memory that the JVM may use for the Java heap +before applying ergonomics heuristics as a fraction of the maximum +amount determined as described in the \f[CB]\-XX:MaxRAM\f[R] option for +small heaps. +A small heap is a heap of approximately 125 MB. +The default value is 2. +.RS +.PP +Use the option \f[CB]\-XX:MinRAMPercentage\f[R] instead. +.RE +.TP .B \f[CB]\-XX:+TraceClassLoading\f[R] Enables tracing of classes as they are loaded. By default, this option is disabled and classes aren\[aq]t traced.