From f8bab2d61d84b4e122ca667c4e458cd2ca29e3b6 Mon Sep 17 00:00:00 2001 From: Christian Biesinger Date: Mon, 18 Nov 2019 16:37:31 -0600 Subject: [PATCH] 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 * 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 --- gdb/ChangeLog | 6 ++++++ gdb/symtab.c | 14 ++++++++++++-- 2 files changed, 18 insertions(+), 2 deletions(-) diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 93258c3d86..838262eba3 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,9 @@ +2019-11-22 Christian Biesinger + + * 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 * contrib/words.sh: Improve words extraction. diff --git a/gdb/symtab.c b/gdb/symtab.c index 0064800313..6affdef58c 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)); } -- 2.34.1