On 08/13/2015 06:47 AM, Leonid Isaev wrote:
I would personally prefer that most packages come with debugging enabled by default. Surely, there will be a performance cost, but speed is not crucial in most cases.
Cheers,
There's no performance impact, just disk space and bandwidth.
Bandwidth is probably the main problem, although anyone who wants to debug will probably be fine with that. I think you guys misunderstood me. The biggest problem IMHO with building debug versions locally is not compiling itself, but setting up the environment. So, I meant that packages come with debugging enabled (compiled with gcc -O0 -g and
On Thu, Aug 13, 2015 at 03:11:58PM +0200, Evan Penner wrote: perhaps ./configure options). This way, there will be not many new packages.
No, the biggest problem with building debug versions locally is that it takes hours of developer time multiplied by every bug found. Why are we wasting such a limited resource when it's so easy not to? Life is finite.
Of course, this is not a good idea for things like FF/Gnome/KDE because of a slow-down, but a performance penalty for smaller programs like vim, links, XFCE4 etc. will not be noticeable (at least I don't see any for a self-compiled xfce4 desktop on a single-core Intel Atom based netbook).
Cheers,
What is this slow-down you keep talking about? I'm not asking to do away with optimization, just give us a way to get the debug symbols without rebuilding. The debug symbols are located in totally different sections from the code/data sections. You can check it with objdump: $ objdump -h a.out a.out: file format elf64-x86-64 Sections: Idx Name Size VMA LMA File off Algn 0 .interp 0000001c 0000000000400200 0000000000400200 00000200 2**0 CONTENTS, ALLOC, LOAD, READONLY, DATA 1 .note.ABI-tag 00000020 000000000040021c 000000000040021c 0000021c 2**2 CONTENTS, ALLOC, LOAD, READONLY, DATA 2 .note.gnu.build-id 00000024 000000000040023c 000000000040023c 0000023c 2**2 CONTENTS, ALLOC, LOAD, READONLY, DATA 3 .hash 00000018 0000000000400260 0000000000400260 00000260 2**3 CONTENTS, ALLOC, LOAD, READONLY, DATA 4 .gnu.hash 0000001c 0000000000400278 0000000000400278 00000278 2**3 CONTENTS, ALLOC, LOAD, READONLY, DATA 5 .dynsym 00000048 0000000000400298 0000000000400298 00000298 2**3 CONTENTS, ALLOC, LOAD, READONLY, DATA 6 .dynstr 00000038 00000000004002e0 00000000004002e0 000002e0 2**0 CONTENTS, ALLOC, LOAD, READONLY, DATA 7 .gnu.version 00000006 0000000000400318 0000000000400318 00000318 2**1 CONTENTS, ALLOC, LOAD, READONLY, DATA 8 .gnu.version_r 00000020 0000000000400320 0000000000400320 00000320 2**3 CONTENTS, ALLOC, LOAD, READONLY, DATA 9 .rela.dyn 00000018 0000000000400340 0000000000400340 00000340 2**3 CONTENTS, ALLOC, LOAD, READONLY, DATA 10 .rela.plt 00000018 0000000000400358 0000000000400358 00000358 2**3 CONTENTS, ALLOC, LOAD, READONLY, DATA 11 .init 00000018 0000000000400370 0000000000400370 00000370 2**2 CONTENTS, ALLOC, LOAD, READONLY, CODE 12 .plt 00000020 0000000000400388 0000000000400388 00000388 2**2 CONTENTS, ALLOC, LOAD, READONLY, CODE 13 .text 000001c8 00000000004003b0 00000000004003b0 000003b0 2**4 CONTENTS, ALLOC, LOAD, READONLY, CODE 14 .fini 0000000e 0000000000400578 0000000000400578 00000578 2**2 CONTENTS, ALLOC, LOAD, READONLY, CODE 15 .rodata 00000004 0000000000400588 0000000000400588 00000588 2**2 CONTENTS, ALLOC, LOAD, READONLY, DATA 16 .eh_frame_hdr 00000024 000000000040058c 000000000040058c 0000058c 2**2 CONTENTS, ALLOC, LOAD, READONLY, DATA 17 .eh_frame 0000007c 00000000004005b0 00000000004005b0 000005b0 2**3 CONTENTS, ALLOC, LOAD, READONLY, DATA 18 .ctors 00000010 0000000000600630 0000000000600630 00000630 2**3 CONTENTS, ALLOC, LOAD, DATA 19 .dtors 00000010 0000000000600640 0000000000600640 00000640 2**3 CONTENTS, ALLOC, LOAD, DATA 20 .jcr 00000008 0000000000600650 0000000000600650 00000650 2**3 CONTENTS, ALLOC, LOAD, DATA 21 .dynamic 000001a0 0000000000600658 0000000000600658 00000658 2**3 CONTENTS, ALLOC, LOAD, DATA 22 .got 00000008 00000000006007f8 00000000006007f8 000007f8 2**3 CONTENTS, ALLOC, LOAD, DATA 23 .got.plt 00000020 0000000000600800 0000000000600800 00000800 2**3 CONTENTS, ALLOC, LOAD, DATA 24 .data 00000010 0000000000600820 0000000000600820 00000820 2**3 CONTENTS, ALLOC, LOAD, DATA 25 .bss 00000010 0000000000600830 0000000000600830 00000830 2**3 ALLOC 26 .comment 00000039 0000000000000000 0000000000000000 00000830 2**0 CONTENTS, READONLY 27 .debug_aranges 00000030 0000000000000000 0000000000000000 00000869 2**0 CONTENTS, READONLY, DEBUGGING 28 .debug_pubnames 0000001b 0000000000000000 0000000000000000 00000899 2**0 CONTENTS, READONLY, DEBUGGING 29 .debug_info 00000055 0000000000000000 0000000000000000 000008b4 2**0 CONTENTS, READONLY, DEBUGGING 30 .debug_abbrev 00000034 0000000000000000 0000000000000000 00000909 2**0 CONTENTS, READONLY, DEBUGGING 31 .debug_line 0000003b 0000000000000000 0000000000000000 0000093d 2**0 CONTENTS, READONLY, DEBUGGING 32 .debug_str 00000026 0000000000000000 0000000000000000 00000978 2**0 CONTENTS, READONLY, DEBUGGING 33 .debug_loc 0000004c 0000000000000000 0000000000000000 0000099e 2**0 CONTENTS, READONLY, DEBUGGING You can see the extra sections (27 through 33). These sections won't be loaded at runtime, so there won't be any performance penalty. Using gdb, you can also examine them at runtime $ gdb ./a.out (gdb) break main (gdb) run (gdb) info files // blah blah .... Local exec file: `/home/kghost/a.out', file type elf64-x86-64. Entry point: 0x4003b0 0x0000000000400200 - 0x000000000040021c is .interp 0x000000000040021c - 0x000000000040023c is .note.ABI-tag 0x000000000040023c - 0x0000000000400260 is .note.gnu.build-id 0x0000000000400260 - 0x0000000000400278 is .hash 0x0000000000400278 - 0x0000000000400294 is .gnu.hash 0x0000000000400298 - 0x00000000004002e0 is .dynsym 0x00000000004002e0 - 0x0000000000400318 is .dynstr 0x0000000000400318 - 0x000000000040031e is .gnu.version 0x0000000000400320 - 0x0000000000400340 is .gnu.version_r 0x0000000000400340 - 0x0000000000400358 is .rela.dyn 0x0000000000400358 - 0x0000000000400370 is .rela.plt 0x0000000000400370 - 0x0000000000400388 is .init 0x0000000000400388 - 0x00000000004003a8 is .plt 0x00000000004003b0 - 0x0000000000400578 is .text 0x0000000000400578 - 0x0000000000400586 is .fini 0x0000000000400588 - 0x000000000040058c is .rodata 0x000000000040058c - 0x00000000004005b0 is .eh_frame_hdr 0x00000000004005b0 - 0x000000000040062c is .eh_frame 0x0000000000600630 - 0x0000000000600640 is .ctors 0x0000000000600640 - 0x0000000000600650 is .dtors 0x0000000000600650 - 0x0000000000600658 is .jcr 0x0000000000600658 - 0x00000000006007f8 is .dynamic 0x00000000006007f8 - 0x0000000000600800 is .got 0x0000000000600800 - 0x0000000000600820 is .got.plt 0x0000000000600820 - 0x0000000000600830 is .data 0x0000000000600830 - 0x0000000000600840 is .bss // blah blah .... So the only penalty is that you need extra disk space to store this information.