* Makefile.in (ggc-common.o): Depend on $(PARAMS_H)

	* doc/invoke.texi (ggc-min-expand, ggc-min-heapsize): Update
	documentation.
	* ggc-common.c: Include params.h
	(ggc_min_expand_heuristic, ggc_min_heapsize_heuristic,
	init_ggc_heuristics): New functions.
	* ggc.h (ggc_min_expand_heuristic, ggc_min_heapsize_heuristic,
	init_ggc_heuristics): Prototype.
	* toplev.c (print_version):  Output GGC heuristics.
	(parse_options_and_default_flags): Call init_ggc_heuristics.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@63268 138bc75d-0d04-0410-961f-82ee72b054a4

6 files changed, 74 insertions, 6 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 746458b18f1..17655e6afa3 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,16 @@
+2003-02-21  Kaveh R. Ghazi  <ghazi@caip.rutgers.edu>
+
+	* Makefile.in (ggc-common.o): Depend on $(PARAMS_H)
+	* doc/invoke.texi (ggc-min-expand, ggc-min-heapsize): Update
+	documentation.
+	* ggc-common.c: Include params.h
+	(ggc_min_expand_heuristic, ggc_min_heapsize_heuristic,
+	init_ggc_heuristics): New functions.
+	* ggc.h (ggc_min_expand_heuristic, ggc_min_heapsize_heuristic,
+	init_ggc_heuristics): Prototype.
+	* toplev.c (print_version):  Output GGC heuristics.
+	(parse_options_and_default_flags): Call init_ggc_heuristics.
+
 Sat Feb 22 02:35:07 CET 2003  Jan Hubicka  <jh@suse.cz>
 
 	* i386.c (def_builtin):  Special case 64bit builtins.
diff --git a/gcc/Makefile.in b/gcc/Makefile.in
index b0920e07e1a..e00b2883356 100644
--- a/gcc/Makefile.in
+++ b/gcc/Makefile.in
@@ -1375,7 +1375,7 @@ gtype-desc.o: gtype-desc.c $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H) varray.h
 	ssa.h cselib.h insn-addr.h
 
 ggc-common.o: ggc-common.c $(CONFIG_H) $(SYSTEM_H) coretypes.h $(GGC_H) \
-	$(HASHTAB_H) toplev.h
+	$(HASHTAB_H) toplev.h $(PARAMS_H)
 
 ggc-simple.o: ggc-simple.c $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H) $(RTL_H) $(TREE_H) \
 	flags.h $(GGC_H) varray.h $(TIMEVAR_H) $(TM_P_H) $(PARAMS_H)
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index f47c51ec666..69aef149145 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -4473,7 +4473,9 @@ collector's heap should be allowed to expand between collections.
 Tuning this may improve compilation speed; it has no effect on code
 generation.
 
-The default is 30%.  Setting this parameter and
+The default is 30% + 70% * (RAM/1GB) with an upper bound of 100% when
+RAM >= 1GB.  If GCC is not able to calculate RAM on a particular
+platform, the lower bound of 30% is used.  Setting this parameter and
 @option{ggc-min-heapsize} to zero causes a full collection to occur at
 every opportunity.  This is extremely slow, but can be useful for
 debugging.
@@ -4486,10 +4488,12 @@ by @option{ggc-min-expand}% beyond @option{ggc-min-heapsize}.  Again,
 tuning this may improve compilation speed, and has no effect on code
 generation.
 
-The default is 4096 (four megabytes).  Setting this parameter very large
-effectively disables garbage collection.  Setting this parameter and
-@option{ggc-min-expand} to zero causes a full collection to occur at
-every opportunity.  
+The default is RAM/8, with a lower bound of 4096 (four megabytes) and an
+upper bound of 131072 (128 megabytes).  If GCC is not able to calculate
+RAM on a particular platform, the lower bound is used.  Setting this
+parameter very large effectively disables garbage collection.  Setting
+this parameter and @option{ggc-min-expand} to zero causes a full
+collection to occur at every opportunity.
 
 @end table
 @end table
diff --git a/gcc/ggc-common.c b/gcc/ggc-common.c
index e9c2f020668..8a8f7ecd313 100644
--- a/gcc/ggc-common.c
+++ b/gcc/ggc-common.c
@@ -27,6 +27,7 @@ Software Foundation, 59 Temple Place - Suite 330, Boston, MA
 #include "hashtab.h"
 #include "ggc.h"
 #include "toplev.h"
+#include "params.h"
 
 #ifdef HAVE_MMAP_FILE
 # include <sys/mman.h>
@@ -624,3 +625,43 @@ gt_pch_restore (f)
 
   gt_pch_restore_stringpool ();
 }
+
+/* Heuristic to set a default for GGC_MIN_EXPAND.  */
+int
+ggc_min_expand_heuristic()
+{
+  double min_expand = physmem_total();
+  
+  /* The heuristic is a percentage equal to 30% + 70%*(RAM/1GB), yielding
+     a lower bound of 30% and an upper bound of 100% (when RAM >= 1GB).  */
+  min_expand /= 1024*1024*1024;
+  min_expand *= 70;
+  min_expand = MIN (min_expand, 70);
+  min_expand += 30;
+
+  return min_expand;
+}
+
+/* Heuristic to set a default for GGC_MIN_HEAPSIZE.  */
+int
+ggc_min_heapsize_heuristic()
+{
+  double min_heap_kbytes = physmem_total() / 1024;
+  
+  /* The heuristic is RAM/8, with a lower bound of 4M and an upper
+     bound of 128M (when RAM >= 1GB).  */
+  min_heap_kbytes /= 8;
+  min_heap_kbytes = MAX (min_heap_kbytes, 4 * 1024);
+  min_heap_kbytes = MIN (min_heap_kbytes, 128 * 1024);
+
+  return min_heap_kbytes;
+}
+
+void
+init_ggc_heuristics ()
+{
+#ifndef ENABLE_GC_ALWAYS_COLLECT
+  set_param_value ("ggc-min-expand", ggc_min_expand_heuristic());
+  set_param_value ("ggc-min-heapsize", ggc_min_heapsize_heuristic());
+#endif
+}
diff --git a/gcc/ggc.h b/gcc/ggc.h
index 86ae60a7d99..17b8e721c7d 100644
--- a/gcc/ggc.h
+++ b/gcc/ggc.h
@@ -262,3 +262,8 @@ extern void ggc_print_common_statistics PARAMS ((FILE *, ggc_statistics *));
 /* Print allocation statistics.  */
 extern void ggc_print_statistics	PARAMS ((void));
 extern void stringpool_statistics	PARAMS ((void));
+
+/* Heuristics.  */
+extern int ggc_min_expand_heuristic PARAMS ((void));
+extern int ggc_min_heapsize_heuristic PARAMS ((void));
+extern void init_ggc_heuristics PARAMS ((void));
diff --git a/gcc/toplev.c b/gcc/toplev.c
index 92bc8adcb49..44898525388 100644
--- a/gcc/toplev.c
+++ b/gcc/toplev.c
@@ -4638,6 +4638,8 @@ print_version (file, indent)
      FILE *file;
      const char *indent;
 {
+  fnotice (file, "GGC heuristics: --param ggc-min-expand=%d --param ggc-min-heapsize=%d\n",
+	   PARAM_VALUE (GGC_MIN_EXPAND), PARAM_VALUE (GGC_MIN_HEAPSIZE));
 #ifndef __VERSION__
 #define __VERSION__ "[?]"
 #endif
@@ -4893,6 +4895,9 @@ parse_options_and_default_flags (argc, argv)
   /* Register the language-independent parameters.  */
   add_params (lang_independent_params, LAST_PARAM);
 
+  /* This must be done after add_params but before argument processing.  */
+  init_ggc_heuristics();
+
   /* Perform language-specific options initialization.  */
   (*lang_hooks.init_options) ();