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Date:   Mon, 29 Apr 2019 16:45:00 +0800
From:   Mao Han <han_mao@c-sky.com>
To:     Palmer Dabbelt <palmer@sifive.com>
Cc:     linux-riscv@lists.infradead.org, guoren@kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH 3/3] riscv: Add support for libdw
Message-ID: <20190429084441.GC22718@vmh-VirtualBox>
References: <99f15d5c74727c31bf8d08b6cf948754e3e09943.1554961908.git.han_mao@c-sky.com>
 <mhng-a74d03ae-cfb4-4e42-8950-f90816975291@palmer-si-x1e>
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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@c-sky.com 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