Re: [PATCH 3/3] riscv: Add support for libdw

[Mao Han]

On Thu, Apr 25, 2019 at 02:11:04PM -0700, Palmer Dabbelt wrote:
> On Thu, 11 Apr 2019 00:53:50 PDT (-0700), han_mao@xxxxxxxxx wrote:
> >This patch add support for DWARF register mappings and libdw registers
> >initialization, which is used by perf callchain analyzing when
> >--call-graph=dwarf is given.
> 
> Is there any way to make this the only backtracer?  It's the only one that's
> likely to be useful on RISC-V without recompiling everything with
> -fno-omit-frame-pointer, which has a major performance hit.
>

Frame pointer is the default record mode in record_callchain_opt.
Some generic modification seems required to change this, default to
use dwarf if riscv and show corresponding message in --help.

Thanks,
Mao Han