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
