[arch-general] wchan info in ps

[Dimitrios Apostolou]

On Sat, 14 Nov 2009, Dimitrios Apostolou wrote:
> Hello list,
>
> is anyone actually getting WCHAN information from either ps or top? To try it 
> just use "ps opid,wchan,cmd". I only get dashes, any idea why?
>

I managed to resolve this issue. Arch builds its kernels (on 32-bit at 
least) without CONFIG_FRAME_POINTER and loses the ability to produce 
correct stacktraces, either with /proc/$PID/wchan or with SysRq-t or with 
gdb. On the other hand it has one more register free so minor 
optimisations can be performed.

Why don't we set CONFIG_FRAME_POINTER=y? WCHAN output is very useful to be 
lost and frankly I don't think performance losses would be perceivable. 
Last but not least I haven't seen this disabled in any other distro.


>
> Thanks,
> Dimitris
>
>