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authorChristian Biesinger <cbiesinger@google.com>2019-11-18 16:37:31 -0600
committerChristian Biesinger <cbiesinger@google.com>2019-11-22 11:42:41 -0600
commitf8bab2d61d84b4e122ca667c4e458cd2ca29e3b6 (patch)
tree05b3a9dc41b308d031b3ed2b084a0f52fecf2001 /gdb
parent85e7588dc4b191326f90d4e2358566d9cc14242a (diff)
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Create a correctly-sized demangled names hashtable
If we have a minsym count, we know the demangled names hashtable will be at least that big. So use that count to size it, so we don't have to resize/rehash it as much. This is a 6% improvement in minsym loading time. 2019-11-22 Christian Biesinger <cbiesinger@google.com> * symtab.c (create_demangled_names_hash): Use per_bfd-> minimal_symbol_count for computing the initial size, if greater than our default size. Change-Id: I1f074d38e1d90af58705ec852f90c84cc034cd2e
Diffstat (limited to 'gdb')
-rw-r--r--gdb/ChangeLog6
-rw-r--r--gdb/symtab.c14
2 files changed, 18 insertions, 2 deletions
diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 93258c3..838262e 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,9 @@
+2019-11-22 Christian Biesinger <cbiesinger@google.com>
+
+ * symtab.c (create_demangled_names_hash): Use per_bfd->
+ minimal_symbol_count for computing the initial size, if greater
+ than our default size.
+
2019-11-22 Tom de Vries <tdevries@suse.de>
* contrib/words.sh: Improve words extraction.
diff --git a/gdb/symtab.c b/gdb/symtab.c
index 0064800..6affdef 100644
--- a/gdb/symtab.c
+++ b/gdb/symtab.c
@@ -770,10 +770,20 @@ create_demangled_names_hash (struct objfile_per_bfd_storage *per_bfd)
/* Choose 256 as the starting size of the hash table, somewhat arbitrarily.
The hash table code will round this up to the next prime number.
Choosing a much larger table size wastes memory, and saves only about
- 1% in symbol reading. */
+ 1% in symbol reading. However, if the minsym count is already
+ initialized (e.g. because symbol name setting was deferred to
+ a background thread) we can initialize the hashtable with a count
+ based on that, because we will almost certainly have at least that
+ many entries. If we have a nonzero number but less than 256,
+ we still stay with 256 to have some space for psymbols, etc. */
+
+ /* htab will expand the table when it is 3/4th full, so we account for that
+ here. +2 to round up. */
+ int minsym_based_count = (per_bfd->minimal_symbol_count + 2) / 3 * 4;
+ int count = std::max (per_bfd->minimal_symbol_count, minsym_based_count);
per_bfd->demangled_names_hash.reset (htab_create_alloc
- (256, hash_demangled_name_entry, eq_demangled_name_entry,
+ (count, hash_demangled_name_entry, eq_demangled_name_entry,
free_demangled_name_entry, xcalloc, xfree));
}