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RE: changing the default hash table size (was improving ld performance)

Hi Nick

> There are no such options at present, but I think that this would be a
> very good idea.  Would you like to develop a patch to do it ?

How's this:

Index: bfd/bfd-in.h
===================================================================
RCS file: /cvs/src/src/bfd/bfd-in.h,v
retrieving revision 1.72
diff -c -w -r1.72 bfd-in.h
*** bfd/bfd-in.h	16 Feb 2004 18:46:40 -0000	1.72
--- bfd/bfd-in.h	11 Mar 2004 09:29:22 -0000
***************
*** 440,445 ****
--- 440,450 ----
     bfd_boolean (*) (struct bfd_hash_entry *, void *),
     void *info);
  
+ /* Allows the default size of a hash table to be configured. New hash
+    tables allocated using bfd_hash_table_init will be created with
+    this size. */
+ extern void bfd_hash_set_default_size (bfd_size_type);
+ 
  #define COFF_SWAP_TABLE (void *) &bfd_coff_std_swap_table
  
  /* User program access to BFD facilities.  */
Index: bfd/hash.c
===================================================================
RCS file: /cvs/src/src/bfd/hash.c,v
retrieving revision 1.11
diff -c -w -r1.11 hash.c
*** bfd/hash.c	1 Dec 2003 06:33:01 -0000	1.11
--- bfd/hash.c	11 Mar 2004 09:29:22 -0000
***************
*** 53,58 ****
--- 53,59 ----
  @* Looking Up or Entering a String::
  @* Traversing a Hash Table::
  @* Deriving a New Hash Table Type::
+ @* Changing the default Hash Table Size::
  @end menu
  
  INODE
***************
*** 87,92 ****
--- 88,97 ----
  	been allocated for a hash table.  This will not free up the
  	<<struct bfd_hash_table>> itself, which you must provide.
  
+ @findex bfd_hash_set_default_size
+ 	Use <<bfd_hash_set_default_size>> to set the default size of
+ 	hash table to use.
+ 
  INODE
  Looking Up or Entering a String, Traversing a Hash Table, Creating and
Freeing a Hash Table, Hash Tables
  SUBSECTION
***************
*** 296,301 ****
--- 301,307 ----
  
  /* The default number of entries to use when creating a hash table.  */
  #define DEFAULT_SIZE (4051)
+ static size_t bfd_default_hash_table_size = DEFAULT_SIZE;
  
  /* Create a new hash table, given a number of entries.  */
  
***************
*** 339,345 ****
  						struct bfd_hash_table *,
  						const char *));
  {
!   return bfd_hash_table_init_n (table, newfunc, DEFAULT_SIZE);
  }
  
  /* Free a hash table.  */
--- 345,351 ----
  						struct bfd_hash_table *,
  						const char *));
  {
!   return bfd_hash_table_init_n (table, newfunc,
bfd_default_hash_table_size);
  }
  
  /* Free a hash table.  */
***************
*** 494,499 ****
--- 500,529 ----
  	}
      }
  }
+ 
+ /* extend this prime list if you want more granularity of hash table size.
*/
+ static bfd_size_type hash_size_primes[] = {
+     4051, 8599, 16699
+ };
+ static const unsigned nhash_size_primes = sizeof(hash_size_primes) /
sizeof(hash_size_primes[0]);
+ 
+ void
+ bfd_hash_set_default_size(bfd_size_type hash_size) {
+   bfd_size_type new_hash_size = hash_size_primes[nhash_size_primes - 1];
+   int index;
+   /* work out best prime number near the hash_size */
+   for (index = 0; index < nhash_size_primes; ++index)
+     {
+       if (hash_size <= hash_size_primes[index])
+         {
+           new_hash_size = hash_size_primes[index];
+           break;
+         }
+     }
+   bfd_default_hash_table_size = new_hash_size;
+   fprintf(stderr, "setting hash size to %d - real size %d\n", hash_size,
new_hash_size);
+ }
+ 
  
  /* A few different object file formats (a.out, COFF, ELF) use a string
     table.  These functions support adding strings to a string table,
Index: ld/ld.h
===================================================================
RCS file: /cvs/src/src/ld/ld.h,v
retrieving revision 1.21
diff -c -w -r1.21 ld.h
*** ld/ld.h	28 Jun 2003 05:28:54 -0000	1.21
--- ld/ld.h	11 Mar 2004 09:29:23 -0000
***************
*** 216,221 ****
--- 216,223 ----
    /* If set, only search library directories explicitly selected
       on the command line.  */
    bfd_boolean only_cmd_line_lib_dirs;
+ 
+   bfd_size_type hash_table_size;
  } ld_config_type;
  
  extern ld_config_type config;
Index: ld/ldmain.c
===================================================================
RCS file: /cvs/src/src/ld/ldmain.c,v
retrieving revision 1.78
diff -c -w -r1.78 ldmain.c
*** ld/ldmain.c	15 Feb 2004 02:24:53 -0000	1.78
--- ld/ldmain.c	11 Mar 2004 09:29:24 -0000
***************
*** 263,268 ****
--- 263,269 ----
    config.has_shared = FALSE;
    config.split_by_reloc = (unsigned) -1;
    config.split_by_file = (bfd_size_type) -1;
+   config.hash_table_size = 0;
    command_line.force_common_definition = FALSE;
    command_line.inhibit_common_definition = FALSE;
    command_line.interpreter = NULL;
***************
*** 337,342 ****
--- 338,346 ----
    ldemul_before_parse ();
    lang_has_input_file = FALSE;
    parse_args (argc, argv);
+ 
+   if (config.hash_table_size != 0)
+     bfd_hash_set_default_size(config.hash_table_size);
  
    ldemul_set_symbols ();
  
Index: ld/lexsup.c
===================================================================
RCS file: /cvs/src/src/ld/lexsup.c,v
retrieving revision 1.70
diff -c -w -r1.70 lexsup.c
*** ld/lexsup.c	7 Dec 2003 00:08:41 -0000	1.70
--- ld/lexsup.c	11 Mar 2004 09:29:24 -0000
***************
*** 116,121 ****
--- 116,122 ----
    OPTION_FORCE_EXE_SUFFIX,
    OPTION_GC_SECTIONS,
    OPTION_NO_GC_SECTIONS,
+   OPTION_HASH_SIZE,
    OPTION_CHECK_SECTIONS,
    OPTION_NO_CHECK_SECTIONS,
    OPTION_NO_UNDEFINED,
***************
*** 325,330 ****
--- 326,333 ----
    { {"no-gc-sections", no_argument, NULL, OPTION_NO_GC_SECTIONS},
        '\0', NULL, N_("Don't remove unused sections (default)"),
        TWO_DASHES },
+   { {"hash-size", required_argument, NULL, OPTION_HASH_SIZE},
+       '\0', NULL, N_("Set default hash table size"), TWO_DASHES },
    { {"help", no_argument, NULL, OPTION_HELP},
        '\0', NULL, N_("Print option help"), TWO_DASHES },
    { {"init", required_argument, NULL, OPTION_INIT},
***************
*** 1205,1210 ****
--- 1208,1216 ----
  	case OPTION_NO_ACCEPT_UNKNOWN_INPUT_ARCH:
  	  command_line.accept_unknown_input_arch = FALSE;
  	  break;
+         case OPTION_HASH_SIZE:
+           config.hash_table_size = strtoul (optarg, NULL, 0);
+           break;
  	case '(':
  	  if (ingroup)
  	    einfo (_("%P%F: may not nest groups (--help for usage)\n"));

-- 
Andy, BlueArc Engineering
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