Re: [Ltp-commits] [patch] Power Management: Fix CPUs' mapping in map_cpuid_pkgid

[Xu, A. <anh...@in...>]

Ignore my verbose explanation, there are bugs in functions map_cpuid_pkgid. This function may lack of consideration for complex CPU topologies.
Nothing wrong with kernel sys interface.

I can provide an CPU topology instance that illustrate this bug.
See the attachment, if we had a cpu topology like correct_mappings.png and function map_cpuid_pkgid can generate a cpu topology like in wrong_mappings.png according to correct_mappings.png
( in each picture, 'physical package' depicted as blue circle, 'core' depicted as purple circle, 'logic CPU' depicted as red circle. The digit in circles are their respective 'id' )


-----Original Message-----
From: Garrett Cooper [mailto:yan...@gm...] 
Sent: Tuesday, December 13, 2011 2:32 PM
To: Xu, Anhua
Cc: ltp...@li...; Song, Youquan
Subject: Re: [Ltp-commits] [patch] Power Management: Fix CPUs' mapping in map_cpuid_pkgid

On Thu, Dec 1, 2011 at 9:20 PM, Xu, Anhua <anh...@in...> wrote:
> >From fcf9dc401bcb91b8691da57173ff06f22eb647af Mon Sep 17 00:00:00 2001
> From: Xu,Anhua <anh...@in...>
> Date: Mon, 28 Nov 2011 22:03:38 +0800
> Subject: [PATCH] Power Management: Fix algorithm in map_cpuid_pkgid
>
> Function map_cpuid_pkgid failed to map CPUs in a 12 cores (2 physical
> sockets, each contains a 6-core package, totally 24 logic CPUs
> considering hyperthreading) x86-64 machine and indicates 18 logic CPUs
> in one package and the other 6 logic CPUS in another package. Whereas
> in fact each package contains 12 logic CPUs (6 cores). The map structures
> generated from map_cpuid_pkgid() are obviously confict with info found in
> /sys/devices/system/cpu/cpu#/topology/physical_package_id

Wouldn't the bug be in how the information is reported via the Linux
kernel and not the test program then?
Thanks,
-Garrett