https://sourceware.org/bugzilla/show_bug.cgi?id=29081
--- Comment #2 from cvs-commit at gcc dot gnu.org <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Martin Liska <mar...@sourceware.org>: https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=e441b55e94c905c6ee4417be3e5d88021d9c5aa6 commit e441b55e94c905c6ee4417be3e5d88021d9c5aa6 Author: Martin Liska <mli...@suse.cz> Date: Wed Aug 3 11:28:10 2022 +0200 add splay tree for info_ptr -> CU mapping While using perf top for MozillaThunderbird I noticed quite some slow dissably call with source code involved. E.g. time ./objdump --start-address=0x0000000004e0dcd0 --stop-address=0x0000000004e0df8b -l -d --no-show-raw-insn -S -C /usr/lib64/thunderbird/libxul.so took 2.071s and I noticed quite some time is spent in find_abstract_instance: 33.46% objdump objdump [.] find_abstract_instance 18.22% objdump objdump [.] arange_add 13.77% objdump objdump [.] read_attribute_value 4.82% objdump objdump [.] comp_unit_maybe_decode_line_info 3.10% objdump libc.so.6 [.] __memset_avx2_unaligned_erms where linked list of CU is iterated when searing for where info_ptr belongs to: : 3452 for (u = unit->prev_unit; u != NULL; u = u->prev_unit) 0.00 : 4c61f7: mov 0x10(%rbx),%rax 0.00 : 4c61fb: test %rax,%rax 0.00 : 4c61fe: je 4c6215 <find_abstract_instance+0x365> : 3453 if (info_ptr >= u->info_ptr_unit && info_ptr < u->end_ptr) 0.00 : 4c6200: cmp 0x60(%rax),%rdx 83.20 : 4c6204: jb 4c620c <find_abstract_instance+0x35c> 0.00 : 4c6206: cmp 0x78(%rax),%rdx 6.89 : 4c620a: jb 4c6270 <find_abstract_instance+0x3c0> : 3452 for (u = unit->prev_unit; u != NULL; u = u->prev_unit) 0.00 : 4c620c: mov 0x10(%rax),%rax 7.90 : 4c6210: test %rax,%rax 0.00 : 4c6213: jne 4c6200 <find_abstract_instance+0x350> The following scan can be replaced with search in a splay tree and with that I can get to 1.5s and there are other symbols where the difference is even bigger. bfd/ChangeLog: PR 29081 * dwarf2.c (struct addr_range): New. (addr_range_intersects): Likewise. (splay_tree_compare_addr_range): Likewise. (splay_tree_free_addr_range): Likewise. (struct dwarf2_debug_file): Add comp_unit_tree. (find_abstract_instance): Use the splay tree when searching for a info_ptr. (stash_comp_unit): Insert to the splay tree. (_bfd_dwarf2_cleanup_debug_info): Clean up the splay tree. -- You are receiving this mail because: You are on the CC list for the bug.
