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Date: Fri, 8 Jul 2016 20:07:46 +0200
From: Ingo Molnar <mingo@kernel.org>
To: "Luck, Tony" <tony.luck@intel.com>
Cc: "Yu, Fenghua" <fenghua.yu@intel.com>, Thomas Gleixner <tglx@linutronix.de>,
        "Anvin, H Peter" <h.peter.anvin@intel.com>,
        Ingo Molnar <mingo@elte.hu>, Borislav Petkov <bp@suse.de>,
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        Peter Zijlstra <peterz@infradead.org>,
        Vikas Shivappa <vikas.shivappa@linux.intel.com>,
        "Shankar, Ravi V" <ravi.v.shankar@intel.com>,
        linux-kernel <linux-kernel@vger.kernel.org>, x86 <x86@kernel.org>
Subject: Re: [PATCH v2 2/3] Documentation, ABI: Add a document entry for
 cache id
Message-ID: <20160708180746.GB4429@gmail.com>
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* Luck, Tony <tony.luck@intel.com> wrote:

> > It means one cache's id is unique in all caches with same cache index number.
> > For example, in all caches with index3 (i.e. level3), cache id 0 is unique to identify
> > a L3 cache. But in caches with index 0 (i.e. Level0), there is also a cache id 0.
> > So cache id is unique in one index. But not unique in two different index.
> 
> > Does that make sense? I hope I express that correctly.
> 
> We use "index" rather than "level" because that is the terminology used
> in /sys/devices/system/cpu/cpu*/cache/index*

Who can we ... thank for that nonsensical naming? :-/

> E.g. on most Intel cpus you'll typically find "index0" is the L1-data cache, 
> "index1" is the L1-instruction cache, "index3" is the L2-unified cache and 
> "index4" is the L3-unified cache.

Crazy. What was wrong with using 'level' or 'depth'?

Thanks,

	Ingo