mirror of
git://gcc.gnu.org/git/gcc.git
synced 2024-12-22 21:19:58 +08:00
787bf7e377
* include/private/gc_priv.h (WARN macro): Add "GC warning:" prefix. (GC_large_alloc_warn_interval, GC_large_alloc_warn_suppressed): declare. * allchblk.c (GC_allchblk_nth): Change text and support reduced frequency for blacklist warning message. * misc.c (GC_large_alloc_warn_interval, GC_large_alloc_warn_suppressed): define. (GC_init_inner): Check GC_NO_BLACKLIST_WARNING and GC_LARGE_ALLOC_WARN_INTERVAL environment variables. * doc/README.environment (GC_NO_BLACKLIST_WARNING): Deprecate. (GC_LARGE_ALLOC_WARN_INTERVAL): Add documentation. * dyn_load.c (_DYNAMIC): Move declaration to file scope. From-SVN: r52053
95 lines
4.6 KiB
Plaintext
95 lines
4.6 KiB
Plaintext
The garbage collector looks at a number of environment variables which are
|
|
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
|
|
process start-up.
|
|
|
|
GC_LOOP_ON_ABORT - Causes the collector abort routine to enter a tight loop.
|
|
This may make it easier to debug, such a process, especially
|
|
for multithreaded platforms that don't produce usable core
|
|
files, or if a core file would be too large. On some
|
|
platforms, this also causes SIGSEGV to be caught and
|
|
result in an infinite loop in a handler, allowing
|
|
similar debugging techniques.
|
|
|
|
GC_PRINT_STATS - Turn on as much logging as is easily feasible without
|
|
adding signifcant runtime overhead. Doesn't work if
|
|
the collector is built with SMALL_CONFIG. Overridden
|
|
by setting GC_quiet. On by default if the collector
|
|
was built without -DSILENT.
|
|
|
|
GC_PRINT_ADDRESS_MAP - Linux only. Dump /proc/self/maps, i.e. various address
|
|
maps for the process, to stderr on every GC. Useful for
|
|
mapping root addresses to source for deciphering leak
|
|
reports.
|
|
|
|
GC_NPROCS=<n> - Linux w/threads only. Explicitly sets the number of processors
|
|
that the GC should expect to use. Note that setting this to 1
|
|
when multiple processors are available will preserve
|
|
correctness, but may lead to really horrible performance.
|
|
|
|
GC_NO_BLACKLIST_WARNING - Prevents the collector from issuing
|
|
warnings about allocations of very large blocks.
|
|
Deprecated. Use GC_LARGE_ALLOC_WARN_INTERVAL instead.
|
|
|
|
GC_LARGE_ALLOC_WARN_INTERVAL=<n> - Print every nth warning about very large
|
|
block allocations, starting with the nth one. Small values
|
|
of n are generally benign, in that a bounded number of
|
|
such warnings generally indicate at most a bounded leak.
|
|
For best results it should be set at 1 during testing.
|
|
Default is 5. Very large numbers effectively disable the
|
|
warning.
|
|
|
|
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:
|
|
|
|
GC_FIND_LEAK - Turns on GC_find_leak and thus leak detection.
|
|
|
|
GC_ALL_INTERIOR_POINTERS - Turns on GC_all_interior_pointers and thus interior
|
|
pointer recognition.
|
|
|
|
GC_DONT_GC - Turns off garbage collection. Use cautiously.
|