perf script not writing out symbol names?

Hi

I'm using 'perf record -e cycles --call-graph dwarf' on Ubuntu 15.04 which is kernel version '3.19.0-18-generic'

At the moment it does not demangle C++ symbols, but otherwise 'perf report' looks fine.

However, if I try to pass the data through the FlameGraph tools, most of the symbols show up as "unknown".

It looks like the 'perf script' tool is not writing out symbol names for most of the events.

Any ideas?

Thanks, Noel Grandin