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