linking performance

[Michael Stahl]

On 14/02/12 13:30, Mark Wielaard wrote:
> Hi,
> 
> Added Tom to the CC, see thread here:
> http://thread.gmane.org/gmane.comp.documentfoundation.libreoffice.devel/24055/focus=24096
> (Although it seems posts from non-subscribers, aka me, are not allowed,
>  so you won't see my earlier reply there. I'll send it to you separately.)
> 
> On Tue, Feb 14, 2012 at 01:07:20PM +0100, Michael Stahl wrote:
>> On 14/02/12 11:52, Michael Meeks wrote:
>>> On Mon, 2012-02-13 at 16:06 +0100, Michael Stahl wrote:

[snip]

>>> Lubos was talking of using some more magic / smaller debug option
>>> in the past: -gdwarf-4
>>>
>>> 	Are you using that ? I believe we turned it off by default again for
>>> some reason or other: potentially we want to add a check for a tolerably
>>> recent toolchain and debugger on the system before defaulting to that
>>> [ it supposedly saved 30% of the size ], but you need gdb 7.3 really.
>>
>> no, AFAIR Lubos enabled that on master and there were some problems with
>> it (gdb was horribly slow or something), so he disabled it again a week
>> later.
> 
> That really needs some investigation (which is why I added Tom to the CC)
> recent GDB versions improved startup performance a lot, so if enabling
> DWARF4 would make GDB startup slower again (which surprises me) that
> would be really bad. Especially since DWARF4 is now the default at least
> on Fedora.
> 
> Could you give some more specifics about what was tried, what the original
> startup times for gdb were and how much change you saw?

hi Mark, Tom,

the revert is here, which includes a link to a gdb bug:

http://cgit.freedesktop.org/libreoffice/core/commit/?id=e87fc0bfde8bd48b449e123c1bdd28e1359e8c77

http://sourceware.org/bugzilla/show_bug.cgi?id=13498

regards,
 michael