# HG changeset patch
# User wenzelm
# Date 1479658230 -3600
# Node ID 2b90410090ee134ebf046670d0b6d0bcadcd6c2c
# Parent  287d4cdf70a084771f6a79b4c2821b13f5d3849a
more on JVM heap space;

diff -r 287d4cdf70a0 -r 2b90410090ee src/Doc/JEdit/JEdit.thy
--- a/src/Doc/JEdit/JEdit.thy	Sun Nov 20 16:22:32 2016 +0100
+++ b/src/Doc/JEdit/JEdit.thy	Sun Nov 20 17:10:30 2016 +0100
@@ -2020,6 +2020,27 @@
 
   \<^bold>\<open>Workaround:\<close> Use native full-screen control of the window manager (notably
   on Mac OS X).
+
+  \<^item> \<^bold>\<open>Problem:\<close> Heap space of the JVM may fill up and render the Prover IDE
+  unresponsive, e.g.\ when editing big Isabelle sessions with many theories.
+
+  \<^bold>\<open>Workaround:\<close> On a 64bit platform, ensure that the JVM runs in 64bit mode,
+  but the Isabelle/ML process remains in 32bit mode! Do not switch Isabelle/ML
+  into 64bit mode in the expectation to be ``more efficient'' --- this
+  requires approx.\ 32\,GB to make sense.
+
+  For the JVM, always use the 64bit version. That is the default on all
+  platforms, except for Windows: the standard download is for win32, but there
+  is a separate download for win64. This implicitly provides a larger default
+  heap for the JVM.
+
+  Moreover, it is possible to increase JVM heap parameters explicitly, by
+  editing platform-specific files (for ``properties'' or ``options'') that are
+  associated with the main app bundle.
+
+  Also note that jEdit provides a heap space monitor in the status line
+  (bottom-right). Double-clicking on that causes full garbage-collection,
+  which sometimes helps in low-memory situations.
 \<close>
 
 end
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