Date: Tue, 13 Dec 2005 23:14:20 -0500
From: Nathan Lynch <ntl@pobox.com>
To: "Zhang, Yanmin" <yanmin.zhang@intel.com>
Cc: linux-kernel@vger.kernel.org,
       "Pallipadi, Venkatesh" <venkatesh.pallipadi@intel.com>
Subject: Re: [PATCH 1/2] Export cpu info by sysfs
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Hello-

Zhang, Yanmin wrote:
> I worked out 2 patches to export cpu topology and cache info by sysfs.
> 
> The first patch is to export cpu topology info including below items
> (attributes) which are similar to /proc/cpuinfo.
> 
> /sys/devices/system/cpu/cpuX/topology/physical_package_id(representing
> the physical package id of  cpu X)
> /sys/devices/system/cpu/cpuX/topology/core_id (representing the cpu core
> id  to cpu X)
> /sys/devices/system/cpu/cpuX/topology/thread_id (representing the cpu
> thread id  to cpu X)
> /sys/devices/system/cpu/cpuX/topology/thread_siblings (representing the
> thread siblings to cpu X)
> /sys/devices/system/cpu/cpuX/topology/core_siblings (represeting the
> core siblings to cpu X)

I haven't looked at the patches in detail, but I have a concern about
this approach.  How is it that making new architecture-specific
attributes under cpu directories in sysfs is preferable to the already
architecture-specific format of /proc/cpuinfo and other proc entries?

If we're going to create a new user interface for exposing system
topology (cores and threads etc), I would like for it to be as
architecture-neutral as possible.  We already do this for numa, for
example.


Nathan
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