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Date:   Wed, 20 Oct 2021 22:25:42 +0200
From:   Peter Zijlstra <peterz@infradead.org>
To:     Tom Lendacky <thomas.lendacky@amd.com>
Cc:     linux-kernel@vger.kernel.org, linux-tip-commits@vger.kernel.org,
        Tim Chen <tim.c.chen@linux.intel.com>,
        Barry Song <song.bao.hua@hisilicon.com>, x86@kernel.org
Subject: Re: [tip: sched/core] sched: Add cluster scheduler level for x86
Message-ID: <20211020202542.GU174703@worktop.programming.kicks-ass.net>
References: <20210924085104.44806-4-21cnbao@gmail.com>
 <163429109791.25758.3107620034958821511.tip-bot2@tip-bot2>
 <9e7b0c92-5a3b-8099-8c69-83a9d62aced4@amd.com>
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On Wed, Oct 20, 2021 at 03:08:41PM -0500, Tom Lendacky wrote:
> On 10/20/21 2:51 PM, Peter Zijlstra wrote:
> > On Wed, Oct 20, 2021 at 08:12:51AM -0500, Tom Lendacky wrote:
> > > On 10/15/21 4:44 AM, tip-bot2 for Tim Chen wrote:
> > > > The following commit has been merged into the sched/core branch of tip:
> 
> > 
> > If it does boot, what does something like:
> > 
> >    for i in /sys/devices/system/cpu/cpu*/topology/*{_id,_list}; do echo -n "${i}: " ; cat $i; done
> > 
> > produce?
> 
> The output is about 160K in size, I'll email it to you off-list.

/sys/devices/system/cpu/cpu0/topology/cluster_cpus_list: 0
/sys/devices/system/cpu/cpu0/topology/core_cpus_list: 0,128

/sys/devices/system/cpu/cpu128/topology/cluster_cpus_list: 128
/sys/devices/system/cpu/cpu128/topology/core_cpus_list: 0,128

So for some reason that thing thinks each SMT thread has it's own L2,
which seems rather unlikely. Or SMT has started to mean something
radically different than it used to be :-)

Let me continue trying to make sense of cacheinfo.c