Given that current directory is the root of the powerline repository the following command may be used:
vim --cmd 'let g:powerline_pyeval="powerline#debug#profile_pyeval"' \
--cmd 'set rtp=powerline/bindings/vim' \
-c 'runtime! plugin/powerline.vim' \
{other arguments if needed}
After some time run :WriteProfiling {filename}
Vim command. Currently this
only works with recent Vim and python-2*. It should be easy to modify
:file:`powerline/bindings/vim/autoload/powerline/debug.vim` to suit other
needs.