Imported GC 6.1 Alpha 3. Finally.

From-SVN: r49698

1 files changed, 42 insertions, 1 deletions

diff --git a/boehm-gc/doc/README.environment b/boehm-gc/doc/README.environment
index 5760342..6b25af1 100644
--- a/boehm-gc/doc/README.environment
+++ b/boehm-gc/doc/README.environment
@@ -1,5 +1,5 @@
 The garbage collector looks at a number of environment variables which are
-the used to affect its operation.  These are examined only on Un*x-like
+then used to affect its operation.  These are examined only on Un*x-like
 platforms.
 
 GC_INITIAL_HEAP_SIZE=<bytes> -	Initial heap size in bytes.  May speed up
@@ -32,6 +32,47 @@ GC_NPROCS=<n> - Linux w/threads only.  Explicitly sets the number of processors
 GC_NO_BLACKLIST_WARNING - Prevents the collector from issuing
 		"Needed to allocate blacklisted block at ..." warnings.
 
+GC_IGNORE_GCJ_INFO - Ignore the type descriptors implicitly supplied by
+		     GC_gcj_malloc and friends.  This is useful for debugging
+		     descriptor generation problems, and possibly for
+		     temporarily working around such problems.  It forces a
+		     fully conservative scan of all heap objects except
+		     those known to be pointerfree, and may thus have other
+		     adverse effects.
+
+GC_PRINT_BACK_HEIGHT - Print max length of chain through unreachable objects
+		     ending in a reachable one.  If this number remains
+		     bounded, then the program is "GC robust".  This ensures
+		     that a fixed number of misidentified pointers can only
+		     result in a bounded space leak.  This currently only
+		     works if debugging allocation is used throughout.
+		     It increases GC space and time requirements appreciably.
+		     This feature is still somewhat experimental, and requires
+		     that the collector have been built with MAKE_BACK_GRAPH
+		     defined.  For details, see Boehm, "Bounding Space Usage
+		     of Conservative Garbage Collectors", POPL 2001, or
+		     http://lib.hpl.hp.com/techpubs/2001/HPL-2001-251.html .
+
+GC_ENABLE_INCREMENTAL - Turn on incremental collection at startup.  Note that,
+		     depending on platform and collector configuration, this
+		     may involve write protecting pieces of the heap to
+		     track modifications.  These pieces may include pointerfree
+		     objects or not.  Although this is intended to be
+		     transparent, it may cause unintended system call failures.
+		     Use with caution.
+
+GC_PAUSE_TIME_TARGET - Set the desired garbage collector pause time in msecs.
+		     This only has an effect if incremental collection is enabled.
+		     If a collection requires appreciably more time than this,
+		     the client will be restarted, and the collector will need
+		     to do additional work to compensate.  The special value
+		     "999999" indicates that pause time is unlimited, and the
+		     incremental collector will behave completely like a
+		     simple generational collector.  If the collector is
+		     configured for parallel marking, and run on a multiprocessor,
+		     incremental collection should only be used with unlimited
+		     pause time.
+
 The following turn on runtime flags that are also program settable.  Checked
 only during initialization.  We expect that they will usually be set through
 other means, but this may help with debugging and testing: