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From: Dan Williams <dan.j.williams@intel.com>
Date: Mon, 25 Mar 2019 13:56:51 -0700
Message-ID: <CAPcyv4h+44Ymcwh-q76knp_Mv3UOG2o6pu6wmRYDRV5sb+KOAw@mail.gmail.com>
Subject: Re: Question about using NVDIMM for Linux Kernel debugging
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To: Dru Nelson <drudru@gmail.com>
Cc: linux-nvdimm <linux-nvdimm@lists.01.org>
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On Mon, Mar 25, 2019 at 1:36 PM Dru Nelson <drudru@gmail.com> wrote:
>
> Hello,
>
> I am doing Linux kernel work on an AMD Ryzen desktop PC.
> In particular, I'm trying to debug some hardware driver issues.
> The challenging aspect is that they that pop up daily and (of course...)
> randomly.
> As you are well aware, this can be painful in a production environment on
> actual hardware.
> Sometimes the computer just reboots or locks up, so having something
> persistent would be ideal.
> I would like to track down the issue by having some basic instrumentation
> of the kernel.
>
> After doing a little research, this looks like a great application for an
> NVDIMM.
>
> I would probably divide the nvdimm with ring buffers for each core of the
> CPU to avoid locks. The logging would just be simple fixed size records
> with a timestamp.
>
> Does this look doable for a reasonably priced NVDIMM?
> Or is there a better solution?

I'd recommend taking a look at ramoops, but that said I've not tried
hooking it up to an NVDIMM backend.

https://github.com/torvalds/linux/blob/master/Documentation/admin-guide/ramoops.rst
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