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From:   Anup Patel <anup@brainfault.org>
Date:   Thu, 5 Dec 2019 22:03:34 +0530
Message-ID: <CAAhSdy1RQw3MVcVT5y1EHr72LDNADKRL5nO2E8OrzBi+tpuvtA@mail.gmail.com>
Subject: Re: [PATCH] RISC-V: Add debug defconfigs
To:     Paul Walmsley <paul.walmsley@sifive.com>
Cc:     Anup Patel <Anup.Patel@wdc.com>,
        Palmer Dabbelt <palmer@dabbelt.com>,
        Albert Ou <aou@eecs.berkeley.edu>,
        Atish Patra <Atish.Patra@wdc.com>,
        Alistair Francis <Alistair.Francis@wdc.com>,
        Christoph Hellwig <hch@lst.de>,
        "linux-riscv@lists.infradead.org" <linux-riscv@lists.infradead.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
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On Thu, Dec 5, 2019 at 8:33 AM Paul Walmsley <paul.walmsley@sifive.com> wrote:
>
> On Thu, 5 Dec 2019, Anup Patel wrote:
>
> > Various Linux kernel DEBUG options have big performance impact
> > so these should not be enabled in RISC-V normal defconfigs.
> >
> > Instead we should have separate RISC-V debug defconfigs having
> > these DEBUG options enabled. This way Linux RISC-V can build both
> > non-debug and debug kernels separately.
>
> I respect your point of view, but until the RISC-V kernel port is more
> mature, I personally am not planning to merge this patch, for reasons
> discussed in the defconfig patch descriptions and the subsequent pull
> request threads.
>
> I'm sure we'll revisit this in the future to realign with the defconfig
> debug settings for more mature architecture ports - but my guess is that
> we'll probably avoid creating debug_defconfigs, since only S390 does that.

We have a lot of users (Yocto and Buildroot) dependent on the Linux
defconfig. I understand that you need DEBUG options for SiFive internal
use but this does not mean all users dependent on Linux defconfig
should be penalized in-terms of performance.

This is the right time to introduce debug defconfigs so that you can
use it for your SiFive internal use and all users dependent on normal
defconfigs are not penalized in-terms of performance.

If you still don't want debug defconfigs then I recommend reverting
your DEBUG options patch and you can find an alternative way to
enable DEBUG options for SiFive internal use.

Regards,
Anup