Make Power MachTen use vfork and perl's malloc

	Message-Id: <v03110701b1c1603eae52@[195.95.102.68]>

p4raw-id: //depot/perl@1298

diff --git a/hints/machten.sh b/hints/machten.sh
index 2485460..75cbc0d 100644 (file)
--- a/hints/machten.sh
+++ b/hints/machten.sh
@@ -13,6 +13,8 @@
 #      Martijn Koster <m.koster@webcrawler.com>
 #      Richard Yeh <rcyeh@cco.caltech.edu>
 #
+# Use vfork and perl's malloc by default
+#                      -- Dominic Dunlop <domo@computer.org> 980630
 # Raise perl's stack size again; cut down reg_infty; document
 #                      -- Dominic Dunlop <domo@computer.org> 980619
 # Use of semctl() can crash system: disable -- Dominic Dunlop 980506
@@ -33,8 +35,35 @@
 
 # Power MachTen is a real memory system and its standard malloc
 # has been optimized for this. Using this malloc instead of Perl's
-# malloc may result in significant memory savings.
-usemymalloc='false'
+# malloc may result in significant memory savings.  In particular,
+# unlike most UNIX memory allocation subsystems, MachTen's free()
+# really does return unneeded process data memory to the system.
+# However, MachTen's malloc() is woefully slow -- maybe 100 times
+# slower than perl's own, so perl's own is usually the better
+# choice.  In order to use perl's malloc(), the sbrk() system call
+# must be simulated using MachTen's malloc().  See malloc.c for
+# precise details of how this is achieved.  Recent improvements
+# to perl's malloc() currently crash MachTen, and so are disabled
+# by -DPLAIN_MALLOC and -DNO_FANCY_MALLOC.
+usemymalloc=${usemymalloc:-y}
+
+# Do not wrap the following long line
+malloc_cflags='ccflags="$ccflags -DPLAIN_MALLOC -DNO_FANCY_MALLOC -DUSE_PERL_SBRK"'
+
+# Note that an empty malloc_cflags appears in config.sh if perl's
+# malloc() is not used.  his is harmless.
+case "$usemymalloc" in
+n) unset malloc_cflags;;
+*) ccflags="$ccflags  -DHIDEMYMALLOC"
+esac
+
+# When MachTen does a fork(), it immediately copies the whole of
+# the parent process' data space for the child.  This can be
+# expensive.  Using vfork() where appropriate avoids this cost.
+d_vfork=${d_vfork:-define}
+
+# Specify a high level of optimization (-O3 wouldn't do much more)
+optimize=${optimize:--O2 -fomit-frame-pointer}
 
 # Make symbol table listings les voluminous
 nmopts=-gp
@@ -89,9 +118,9 @@ then
        X=`expr $X / 2`
        stack_size=`expr $stack_size \* 2`
     done
+    X=`expr $stack_size \* 1024`
 fi
 
-X=`expr $stack_size \* 1024`
 ldflags="$ldflags -Xlstack=$X"
 ccflags="$ccflags -DREG_INFTY=$reg_infty"
 
@@ -141,11 +170,21 @@ During Configure, you may see the message
 Select the default answer: semctl() is buggy, and perl should be built
 without it.
 
+Similarly, when you see
+
+*** WHOA THERE!!! ***
+    The recommended value for \$d_vfork on this machine was "define"!
+    Keep the recommended value? [y]
+
+select the default answer: vfork() works, and avoids expensive data
+copying.
+
 At the end of Configure, you will see a harmless message
 
 Hmm...You had some extra variables I don't know about...I'll try to keep 'em.
        Propagating recommended variable dont_use_nlink
         Propagating recommended variable nmopts
+        Propagating recommended variable malloc_cflags...
         Propagating recommended variable reg_infty
 Read the File::Find documentation for more information about dont_use_nlink
 

diff --git a/malloc.c b/malloc.c
index ea00e5a..a12f768 100644 (file)
--- a/malloc.c
+++ b/malloc.c
@@ -51,10 +51,17 @@
     # Use table lookup to decide in which bucket a given allocation will go.
     SMALL_BUCKET_VIA_TABLE     !NO_FANCY_MALLOC
 
-    # Use system-malloc() to emulate sbrk(). Normally only used with broken
-    # sbrk()s.
+    # Use a perl-defined sbrk() instead of the (presumably broken or
+    # missing) system-supplied sbrk().
+    USE_PERL_SBRK              undef
+
+    # Use system malloc() (or calloc() etc.) to emulate sbrk(). Normally
+    # only used with broken sbrk()s.
     PERL_SBRK_VIA_MALLOC       undef
 
+    # Which allocator to use if PERL_SBRK_VIA_MALLOC
+    SYSTEM_ALLOC(a)            malloc(a)
+
     # Disable memory overwrite checking with DEBUGGING.  Memory and speed
     # optimization, error reporting pessimization.
     NO_RCHECK                  undef
@@ -94,9 +101,6 @@
     # This many continuous sbrk()s compensate for one discontinuous one.
     SBRK_FAILURE_PRICE         50
 
-    # Which allocator to use if PERL_SBRK_VIA_MALLOC
-    SYSTEM_ALLOC(a)            malloc(a)
-
   This implementation assumes that calling PerlIO_printf() does not
   result in any memory allocation calls (used during a panic).
 
@@ -1546,9 +1550,27 @@ dump_mstats(char *s)
 #      define PERL_SBRK_VIA_MALLOC
 #   endif
 
+#   ifdef __MACHTEN_PPC__
+#      define PERL_SBRK_VIA_MALLOC
+/*
+ * MachTen's malloc() returns a buffer aligned on a two-byte boundary.
+ * While this is adequate, it may slow down access to longer data
+ * types by forcing multiple memory accesses.  It also causes
+ * complaints when RCHECK is in force.  So we allocate six bytes
+ * more than we need to, and return an address rounded up to an
+ * eight-byte boundary.
+ *
+ * 980701 Dominic Dunlop <domo@computer.org>
+ */
+#      define SYSTEM_ALLOC(a) ((void *)(((unsigned)malloc((a)+6)+6)&~7))
+#   endif
+
 #   ifdef PERL_SBRK_VIA_MALLOC
 #      if defined(HIDEMYMALLOC) || defined(EMBEDMYMALLOC)
-#         undef malloc
+#         undef malloc         /* Expose names that  */
+#         undef calloc         /* HIDEMYMALLOC hides */
+#         undef realloc
+#         undef free
 #      else
 #         include "Error: -DPERL_SBRK_VIA_MALLOC needs -D(HIDE|EMBED)MYMALLOC"
 #      endif
@@ -1558,7 +1580,9 @@ dump_mstats(char *s)
 /* frequent core dumps within nxzonefreenolock. This sbrk routine put an */
 /* end to the cores */
 
-#      define SYSTEM_ALLOC(a) malloc(a)
+#      ifndef SYSTEM_ALLOC
+#         define SYSTEM_ALLOC(a) malloc(a)
+#      endif
 
 #   endif  /* PERL_SBRK_VIA_MALLOC */