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objtool: Optimize !vmlinux.o again

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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>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lkml.kernel.org/r/20200416115119.167588731@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Peter Zijlstra
2020-03-12 14:29:38 +01:00
committed by Ingo Molnar
parent c4a33939a7
commit 34f7c96d96
3 changed files with 52 additions and 26 deletions
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tools/objtool/elf.h
+8 -5
View File
@@ -70,17 +70,19 @@ struct rela {
bool jump_table_start;
};
#define ELF_HASH_BITS 20
struct elf {
Elf *elf;
GElf_Ehdr ehdr;
int fd;
char *name;
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(rela_hash, 20);
DECLARE_HASHTABLE(symbol_hash, ELF_HASH_BITS);
DECLARE_HASHTABLE(symbol_name_hash, ELF_HASH_BITS);
DECLARE_HASHTABLE(section_hash, ELF_HASH_BITS);
DECLARE_HASHTABLE(section_name_hash, ELF_HASH_BITS);
DECLARE_HASHTABLE(rela_hash, ELF_HASH_BITS);
};
#define OFFSET_STRIDE_BITS 4
@@ -127,6 +129,7 @@ struct section *elf_create_rela_section(struct elf *elf, struct section *base);
int elf_rebuild_rela_section(struct section *sec);
int elf_write(struct elf *elf);
void elf_close(struct elf *elf);
void elf_add_rela(struct elf *elf, struct rela *rela);
#define for_each_sec(file, sec) \
list_for_each_entry(sec, &file->elf->sections, list)