linux-kernel - Re: [PATCH v7 3/6] cpufreq: powernv: Remove cpu_to_chip

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Message-ID: <20160128082840.GI3935@vireshk>
Date:	Thu, 28 Jan 2016 13:58:40 +0530
From:	Viresh Kumar <viresh.kumar@...aro.org>
To:	Shilpasri G Bhat <shilpa.bhat@...ux.vnet.ibm.com>
Cc:	linuxppc-dev@...abs.org, linux-kernel@...r.kernel.org,
	rjw@...ysocki.net, linux-pm@...r.kernel.org, pc@...ibm.com,
	anton@...ba.org, ego@...ux.vnet.ibm.com,
	shreyas@...ux.vnet.ibm.com, bsingharora@...il.com,
	mpe@...erman.id.au
Subject: Re: [PATCH v7 3/6] cpufreq: powernv: Remove cpu_to_chip_id() from
 hot-path

On 28-01-16, 12:55, Shilpasri G Bhat wrote:
> cpu_to_chip_id() does a DT walk through to find out the chip id by
> taking a contended device tree lock. This adds an unnecessary overhead
> in a hot path. So instead of calling cpu_to_chip_id() everytime cache
> the chip ids for all cores in the array 'core_to_chip_map' and use it
> in the hotpath.
> 
> Reported-by: Anton Blanchard <anton@...ba.org>
> Signed-off-by: Shilpasri G Bhat <shilpa.bhat@...ux.vnet.ibm.com>
> ---
> Changes from v6:
> - Minor changes to move the code 'cpumask_copy()' after 'core_to_chip_map'
>   is allocated.
> - Move 'kfree(chips)' to a separate patch.

See, you weren't that bad :)

Just that you missed saying that individual patches contain
version-log in cover-letter :)

Acked-by: Viresh Kumar <viresh.kumar@...aro.org>

-- 
viresh