Re: gdb eats 100% cpu for relative long time when I single step one instruction

[Thomas Glanzmann <sithglan@stud.uni-erlangen.de>]

Hello,
I compiled gdb with profiling and did my workload:

	Each sample counts as 0.01 seconds.
	  %   cumulative   self              self     total
	 time   seconds   seconds    calls   s/call   s/call  name
	 64.71    127.12   127.12  2169997     0.00     0.00  lookup_minimal_symbol_by_pc_section
	  2.42    131.88     4.76                             print_insn
	  1.95    135.71     3.83   723364     0.00     0.00  find_pc_sect_psymtab
	  1.72    139.09     3.39   723354     0.00     0.00  find_pc_sect_symtab
	  1.68    142.40     3.31  6052249     0.00     0.00  tui_file_adjust_strbuf
	  1.28    144.92     2.52  2170204     0.00     0.00  find_pc_sect_section
	  1.08    147.03     2.12  6052860     0.00     0.00  tui_file_fputs
	  1.04    149.07     2.04 21819200     0.00     0.00  xmalloc

and this is the backtrace:

	(gdb) bt
	#0  0x080f12f2 in find_pc_sect_psymtab ()
	#1  0x080f2597 in find_pc_sect_symtab ()
	#2  0x080f0545 in blockvector_for_pc_sect ()
	#3  0x080f0624 in block_for_pc_sect ()
	#4  0x080ce0e1 in find_pc_sect_function ()
	#5  0x080ee196 in build_address_symbolic ()
	#6  0x080ee028 in print_address_symbolic ()
	#7  0x080ee3b3 in print_address ()
	#8  0x080bfe66 in tui_disassemble ()
	#9  0x080bffe7 in tui_find_disassembly_address ()
	#10 0x080c04be in tui_get_low_disassembly_address ()
	#11 0x080c553a in tui_show_frame_info ()
	#12 0x080c157f in tui_selected_frame_level_changed_hook ()
	#13 0x0808abed in select_frame ()
	#14 0x08103fd2 in normal_stop ()
	#15 0x08101b3b in proceed ()
	#16 0x080ff125 in step_1 ()
	#17 0x080fef27 in nexti_command ()
	#18 0x080b3812 in do_cfunc ()
	#19 0x080b5709 in cmd_func ()
	#20 0x08083ec5 in execute_command ()
	#21 0x0810eb5b in command_handler ()
	#22 0x0810f1c6 in command_line_handler ()
	#23 0x082021e0 in rl_callback_read_char () at callback.c:123
	#24 0x0810e420 in rl_callback_read_char_wrapper ()
	#25 0x0810ea18 in stdin_event_handler ()
	#26 0x0810dd60 in handle_file_event ()
	#27 0x0810d7e7 in process_event ()
	#28 0x0810d838 in gdb_do_one_event ()
	#29 0x08083b41 in do_catch_errors ()
	#30 0x08083936 in catcher ()
	#31 0x08083b9c in catch_errors ()
	#32 0x080c190e in tui_command_loop ()
	#33 0x0810b6bc in current_interp_command_loop ()
	#34 0x0807b44c in captured_command_loop ()
	#35 0x08083b41 in do_catch_errors ()
	#36 0x08083936 in catcher ()
	#37 0x08083b9c in catch_errors ()
	#38 0x0807c1ec in captured_main ()
	#39 0x08083b41 in do_catch_errors ()
	#40 0x08083936 in catcher ()
	#41 0x08083b9c in catch_errors ()
	#42 0x0807c224 in gdb_main ()
	#43 0x0807b437 in main ()

Greetings,
	Thomas