[PATCH] powerpc/configs: Enable function trace by default

[Anton Blanchard]

Hi Balbir,

> > FTRACE is quite CPU consumming, shouldn't it really be on by
> > default ?  
> 
> It does some work at boot to NOP out function entry points at _mcount
> locations. Is that what you are referring to? Or the overhead of the
> code in terms of size? Most distro kernels have tracing on by default.
> 
> The rest of the overhead is enablement based.

Unfortunately the overhead is somewhat high without
CONFIG_MPROFILE_KERNEL, and enabling that option will break old
toolchains. It would be great if we could automatically enable it based
on the toolchain.

Even with CONFIG_MPROFILE_KERNEL enabled, we aren't noping out the
redundant mflr at the start of each function.

Anton