linux-kernel - Re: [UPDATED PATCH 01/10] x86: Add topology_max_smt

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Date:	Sat, 7 May 2016 10:11:33 +0200 (CEST)
From:	Thomas Gleixner <tglx@...utronix.de>
To:	Andi Kleen <andi@...stfloor.org>
cc:	Peter Zijlstra <peterz@...radead.org>, acme@...nel.org,
	jolsa@...nel.org, linux-kernel@...r.kernel.org,
	Andi Kleen <ak@...ux.intel.com>, x86@...nel.org
Subject: Re: [UPDATED PATCH 01/10] x86: Add topology_max_smt_threads()

On Fri, 6 May 2016, Andi Kleen wrote:

> For SMT specific workarounds it is useful to know if SMT is active
> on any online CPU in the system. This currently requires a loop
> over all online CPUs.
>     
> Add a global variable that is updated with the maximum number
> of smt threads on any CPU on online/offline, and use it for
> topology_max_smt_threads()
>     
> The single call is easier to use than a loop.
>     
> Not exported to user space because user space already can use
> the existing sibling interfaces to find this out.

Reviewed-by: Thomas Gleixner <tglx@...utronix.de>