Messages in this thread Patch in this message | | | Date | Wed, 18 Mar 2020 14:20:25 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH v2 17/19] objtool: Optimize !vmlinux.o again |
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On Tue, Mar 17, 2020 at 06:02:51PM +0100, Peter Zijlstra wrote: > When doing kbuild tests to see if the objtool changes affected those I > found that there was a measurable regression: > > pre post > > real 1m13.594 1m16.488s > user 34m58.246s 35m23.947s > sys 4m0.393s 4m27.312s > > Perf showed that for small files the increased hash-table sizes were a > measurable difference. Since we already have -l "vmlinux" to > distinguish between the modes, make it also use a smaller portion of > the hash-tables. > > This flips it into a small win: > > real 1m14.143s > user 34m49.292s > sys 3m44.746s > > Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
There was one 'elf_' prefixing gone missing. Updated patch below.
--- tools/objtool/elf.c | 53 ++++++++++++++++++++++++++++++++++------------------ tools/objtool/elf.h | 4 +-- 2 files changed, 37 insertions(+), 20 deletions(-)
--- a/tools/objtool/elf.c +++ b/tools/objtool/elf.c @@ -27,6 +27,22 @@ static inline u32 str_hash(const char *s return jhash(str, strlen(str), 0); } +static inline int elf_hash_bits(void) +{ + return vmlinux ? 20 : 16; +} + +#define elf_hash_add(hashtable, node, key) \ + hlist_add_head(node, &hashtable[hash_min(key, elf_hash_bits())]) + +static void elf_hash_init(struct hlist_head *table) +{ + __hash_init(table, 1U << elf_hash_bits()); +} + +#define elf_hash_for_each_possible(name, obj, member, key) \ + hlist_for_each_entry(obj, &name[hash_min(key, elf_hash_bits())], member) + static void rb_add(struct rb_root *tree, struct rb_node *node, int (*cmp)(struct rb_node *, const struct rb_node *)) { @@ -115,7 +131,7 @@ struct section *find_section_by_name(str { struct section *sec; - hash_for_each_possible(elf->section_name_hash, sec, name_hash, str_hash(name)) + elf_hash_for_each_possible(elf->section_name_hash, sec, name_hash, str_hash(name)) if (!strcmp(sec->name, name)) return sec; @@ -127,7 +143,7 @@ static struct section *find_section_by_i { struct section *sec; - hash_for_each_possible(elf->section_hash, sec, hash, idx) + elf_hash_for_each_possible(elf->section_hash, sec, hash, idx) if (sec->idx == idx) return sec; @@ -138,7 +154,7 @@ static struct symbol *find_symbol_by_ind { struct symbol *sym; - hash_for_each_possible(elf->symbol_hash, sym, hash, idx) + elf_hash_for_each_possible(elf->symbol_hash, sym, hash, idx) if (sym->idx == idx) return sym; @@ -205,7 +221,7 @@ struct symbol *find_symbol_by_name(struc { struct symbol *sym; - hash_for_each_possible(elf->symbol_name_hash, sym, name_hash, str_hash(name)) + elf_hash_for_each_possible(elf->symbol_name_hash, sym, name_hash, str_hash(name)) if (!strcmp(sym->name, name)) return sym; @@ -224,7 +240,7 @@ struct rela *find_rela_by_dest_range(str sec = sec->rela; for_offset_range(o, offset, offset + len) { - hash_for_each_possible(elf->rela_hash, rela, hash, + elf_hash_for_each_possible(elf->rela_hash, rela, hash, sec_offset_hash(sec, o)) { if (rela->sec != sec) continue; @@ -309,8 +325,8 @@ static int read_sections(struct elf *elf sec->len = sec->sh.sh_size; list_add_tail(&sec->list, &elf->sections); - hash_add(elf->section_hash, &sec->hash, sec->idx); - hash_add(elf->section_name_hash, &sec->name_hash, str_hash(sec->name)); + elf_hash_add(elf->section_hash, &sec->hash, sec->idx); + elf_hash_add(elf->section_name_hash, &sec->name_hash, str_hash(sec->name)); } if (stats) @@ -394,8 +410,8 @@ static int read_symbols(struct elf *elf) else entry = &sym->sec->symbol_list; list_add(&sym->list, entry); - hash_add(elf->symbol_hash, &sym->hash, sym->idx); - hash_add(elf->symbol_name_hash, &sym->name_hash, str_hash(sym->name)); + elf_hash_add(elf->symbol_hash, &sym->hash, sym->idx); + elf_hash_add(elf->symbol_name_hash, &sym->name_hash, str_hash(sym->name)); } if (stats) @@ -504,7 +520,7 @@ static int read_relas(struct elf *elf) } list_add_tail(&rela->list, &sec->rela_list); - hash_add(elf->rela_hash, &rela->hash, rela_hash(rela)); + elf_hash_add(elf->rela_hash, &rela->hash, rela_hash(rela)); nr_rela++; } max_rela = max(max_rela, nr_rela); @@ -531,15 +547,16 @@ struct elf *elf_read(const char *name, i perror("malloc"); return NULL; } - memset(elf, 0, sizeof(*elf)); + memset(elf, 0, offsetof(struct elf, sections)); - hash_init(elf->symbol_hash); - hash_init(elf->symbol_name_hash); - hash_init(elf->section_hash); - hash_init(elf->section_name_hash); - hash_init(elf->rela_hash); INIT_LIST_HEAD(&elf->sections); + elf_hash_init(elf->symbol_hash); + elf_hash_init(elf->symbol_name_hash); + elf_hash_init(elf->section_hash); + elf_hash_init(elf->section_name_hash); + elf_hash_init(elf->rela_hash); + elf->fd = open(name, flags); if (elf->fd == -1) { fprintf(stderr, "objtool: Can't open '%s': %s\n", @@ -676,8 +693,8 @@ struct section *elf_create_section(struc shstrtab->changed = true; list_add_tail(&sec->list, &elf->sections); - hash_add(elf->section_hash, &sec->hash, sec->idx); - hash_add(elf->section_name_hash, &sec->name_hash, str_hash(sec->name)); + elf_hash_add(elf->section_hash, &sec->hash, sec->idx); + elf_hash_add(elf->section_name_hash, &sec->name_hash, str_hash(sec->name)); return sec; } --- a/tools/objtool/elf.h +++ b/tools/objtool/elf.h @@ -78,8 +78,8 @@ struct elf { struct list_head sections; DECLARE_HASHTABLE(symbol_hash, 20); DECLARE_HASHTABLE(symbol_name_hash, 20); - DECLARE_HASHTABLE(section_hash, 16); - DECLARE_HASHTABLE(section_name_hash, 16); + DECLARE_HASHTABLE(section_hash, 20); + DECLARE_HASHTABLE(section_name_hash, 20); DECLARE_HASHTABLE(rela_hash, 20); };
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