Re: [PATCH v9 0/8] Parallel CPU bringup for x86_64

From: Piotr Gorski <piotrgorski@cachyos.org>
To: Oleksandr Natalenko <oleksandr@natalenko.name>,
	David Woodhouse <dwmw2@infradead.org>
Cc: tglx@linutronix.de, kim.phillips@amd.com,
	Usama Arif <usama.arif@bytedance.com>,
	arjan@linux.intel.com, mingo@redhat.com, bp@alien8.de,
	dave.hansen@linux.intel.com, hpa@zytor.com, x86@kernel.org,
	pbonzini@redhat.com, paulmck@kernel.org,
	linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
	rcu@vger.kernel.org, mimoja@mimoja.de, hewenliang4@huawei.com,
	thomas.lendacky@amd.com, seanjc@google.com,
	pmenzel@molgen.mpg.de, fam.zheng@bytedance.com,
	punit.agrawal@bytedance.com, simon.evans@bytedance.com,
	liangma@liangbit.com
Subject: Re: [PATCH v9 0/8] Parallel CPU bringup for x86_64
Date: Mon, 20 Feb 2023 23:22:00 +0100	[thread overview]
Message-ID: <84737fa2-1838-cb7d-7624-5eb9a46a4d0e@cachyos.org> (raw)
In-Reply-To: <982e1d6140705414e8fd60b990bd259a@natalenko.name>

Hello.

In my case, admittedly, the error does not occur, while I have 
information from a friend that AMD FX 6300 only shows 1 core when using 
smp boot patchset, so mentioned Oleksandr. Probably soon friend will 
join the discussion and will be able to provide more information.

W dniu 20.02.2023 o 22:23, Oleksandr Natalenko pisze:
> Hello.
>
> On 20.02.2023 21:31, David Woodhouse wrote:
>> On Mon, 2023-02-20 at 17:40 +0100, Oleksandr Natalenko wrote:
>>> On pondělí 20. února 2023 17:20:13 CET David Woodhouse wrote:
>>> > On Mon, 2023-02-20 at 17:08 +0100, Oleksandr Natalenko wrote:
>>> > >
>>> > > I've applied this to the v6.2 kernel, and suspend/resume broke on
>>> > > my
>>> > > Ryzen 5950X desktop. The machine suspends just fine, but on
>>> > > resume
>>> > > the screen stays blank, and there's no visible disk I/O.
>>> > >
>>> > > Reverting the series brings suspend/resume back to working state.
>>> >
>>> > Hm, thanks. What if you add 'no_parallel_bringup' on the command
>>> > line?
>>>
>>> If the `no_parallel_bringup` param is added, the suspend/resume
>>> works.
>>
>> Thanks for the testing. Can I ask you to do one further test: apply the
>> series only as far as patch 6/8 'x86/smpboot: Support parallel startup
>> of secondary CPUs'.
>>
>> That will do the new startup asm sequence where each CPU finds its own
>> per-cpu data so it *could* work in parallel, but doesn't actually do
>> the bringup in parallel yet.
>
> With patches 1 to 6 (including) applied and no extra cmdline params 
> added the resume doesn't work.
>
>> Does your box have a proper serial port?
>
> No, sorry. I know it'd help with getting logs, and I do have a 
> serial-to-USB cable that I use for another machine, but in this one 
> the port is not routed to outside. I think I can put a header there as 
> the motherboard does have pins, but I'd have to buy one first. In 
> theory, I can do that, but that won't happen within the next few weeks.
>
> P.S. Piotr Gorski (in Cc) also reported this: "My friend from CachyOS 
> can confirm bugs with smpboot patches. AMD FX 6300 only shows 1 core 
> when using smp boot patchset". Probably, he can reply to this thread 
> and provide more details.
>