linux-kernel - Re: [patch 07/11] x86/perf/uncore: Track packages not per cpu data

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Message-ID: <878u2j9gjr.fsf@tassilo.jf.intel.com>
Date:	Wed, 17 Feb 2016 13:24:08 -0800
From:	Andi Kleen <andi@...stfloor.org>
To:	Stephane Eranian <eranian@...gle.com>
Cc:	Thomas Gleixner <tglx@...utronix.de>,
	LKML <linux-kernel@...r.kernel.org>,
	Peter Zijlstra <peterz@...radead.org>,
	Ingo Molnar <mingo@...nel.org>, Borislav Petkov <bp@...en8.de>,
	Harish Chegondi <harish.chegondi@...el.com>,
	Kan Liang <kan.liang@...el.com>,
	Andi Kleen <andi.kleen@...el.com>
Subject: Re: [patch 07/11] x86/perf/uncore: Track packages not per cpu data

Stephane Eranian <eranian@...gle.com> writes:

>>
> Let's assume  you have a system with 48 cpus with HT on, then
> you have  2 processor sockets, which is correct. But then you further
> assume that  topology_physical_package_id() will return 0 or 1 in this case.
> In other words, that physical id are always assigned from 0 to N in a contiguous
> manner.
>
> Do we know for sure that this is always the case for all Intel systems
> and that no
> weird BIOS is assigning random numbers for phys_proc_id?

I don't believe that is a safe assumption.

-Andi

-- 
ak@...ux.intel.com -- Speaking for myself only