Re: [PATCH v3] topology: make core_mask include at least cluster_siblings

From: Darren Hart <darren@os.amperecomputing.com>
To: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>,
	Will Deacon <will@kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Linux Arm <linux-arm-kernel@lists.infradead.org>,
	Sudeep Holla <sudeep.holla@arm.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	"Rafael J. Wysocki" <rafael@kernel.org>,
	Catalin Marinas <Catalin.Marinas@arm.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Barry Song <song.bao.hua@hisilicon.com>,
	Valentin Schneider <Valentin.Schneider@arm.com>,
	"D . Scott Phillips" <scott@os.amperecomputing.com>,
	Ilkka Koskinen <ilkka@os.amperecomputing.com>,
	stable@vger.kernel.org
Subject: Re: [PATCH v3] topology: make core_mask include at least cluster_siblings
Date: Mon, 14 Mar 2022 09:56:24 -0700	[thread overview]
Message-ID: <Yi9zuL8RZyYu1dVL@fedora> (raw)
In-Reply-To: <35344252-5284-b08e-fec7-6dc99476b4b0@arm.com>

On Mon, Mar 14, 2022 at 10:37:21AM +0100, Dietmar Eggemann wrote:
> On 09/03/2022 19:26, Darren Hart wrote:
> > On Wed, Mar 09, 2022 at 01:50:07PM +0100, Dietmar Eggemann wrote:
> >> On 08/03/2022 18:49, Darren Hart wrote:
> >>> On Tue, Mar 08, 2022 at 05:03:07PM +0100, Dietmar Eggemann wrote:
> >>>> On 08/03/2022 12:04, Vincent Guittot wrote:
> >>>>> On Tue, 8 Mar 2022 at 11:30, Will Deacon <will@kernel.org> wrote:
> >>
> >> [...]
> >>
> >>>> IMHO, if core_mask weight is 1, MC will be removed/degenerated anyway.
> >>>>
> >>>> This is what I get on my Ampere Altra (I guess I don't have the ACPI
> >>>> changes which would let to a CLS sched domain):
> >>>>
> >>>> # cat /sys/kernel/debug/sched/domains/cpu0/domain*/name
> >>>> DIE
> >>>> NUMA
> >>>> root@oss-altra01:~# zcat /proc/config.gz | grep SCHED_CLUSTER
> >>>> CONFIG_SCHED_CLUSTER=y
> >>>
> >>> I'd like to follow up on this. Would you share your dmidecode BIOS
> >>> Information section?
> >>
> >> # dmidecode -t 0
> >> # dmidecode 3.2
> >> Getting SMBIOS data from sysfs.
> >> SMBIOS 3.2.0 present.
> >>
> >> Handle 0x0000, DMI type 0, 26 bytes
> >> BIOS Information
> >> 	Vendor: Ampere(TM)
> >> 	Version: 0.9.20200724
> >> 	Release Date: 2020/07/24
> >> 	ROM Size: 7680 kB
> >> 	Characteristics:
> >> 		PCI is supported
> >> 		BIOS is upgradeable
> >> 		Boot from CD is supported
> >> 		Selectable boot is supported
> >> 		ACPI is supported
> >> 		UEFI is supported
> >> 	BIOS Revision: 5.15
> >> 	Firmware Revision: 0.6
> >>
> > 
> > Thank you, I'm following internally and will get with you.
> 
> Looks like in my PPTT, the `Processor Hierarchy Nodes` which represents
> cluster nodes have no valid `ACPI Processor ID`.

Thanks, I'm looking for the right person to get us the latest information
available this. Will follow up once I have.

-- 
Darren Hart
Ampere Computing / OS and Kernel

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