From: Balbir Singh <bsingharora@gmail.com>
To: Shilpasri G Bhat <shilpa.bhat@linux.vnet.ibm.com>
Cc: linuxppc-dev@ozlabs.org, linux-kernel@vger.kernel.org,
rjw@rjwysocki.net, viresh.kumar@linaro.org,
linux-pm@vger.kernel.org, pc@us.ibm.com, anton@samba.org,
ego@linux.vnet.ibm.com, shreyas@linux.vnet.ibm.com
Subject: Re: [PATCH v6 2/5] cpufreq: powernv: Remove cpu_to_chip_id() from hot-path
Date: Sat, 23 Jan 2016 19:59:20 +1100 [thread overview]
Message-ID: <20160123195920.552990ed@cotter.ozlabs.ibm.com> (raw)
In-Reply-To: <1453447145-17722-3-git-send-email-shilpa.bhat@linux.vnet.ibm.com>
On Fri, 22 Jan 2016 12:49:02 +0530
Shilpasri G Bhat <shilpa.bhat@linux.vnet.ibm.com> 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@samba.org>
> Signed-off-by: Shilpasri G Bhat <shilpa.bhat@linux.vnet.ibm.com>
> Reviewed-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
snip
Does the core_to_chip_map need to be updated/refreshed on/after/ a
cpu (core) hotplug? I presume id's don't change
Balbir
next prev parent reply other threads:[~2016-01-23 8:59 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-22 7:19 [PATCH v6 0/5] cpufreq: powernv: Redesign the presentation of throttle notification and solve bug-fixes in the driver Shilpasri G Bhat
2016-01-22 7:19 ` [PATCH v6 1/5] cpufreq: powernv: Hot-plug safe the kworker thread Shilpasri G Bhat
2016-01-25 5:49 ` Viresh Kumar
2016-01-22 7:19 ` [PATCH v6 2/5] cpufreq: powernv: Remove cpu_to_chip_id() from hot-path Shilpasri G Bhat
2016-01-23 8:59 ` Balbir Singh [this message]
2016-01-25 5:38 ` Gautham R Shenoy
2016-01-25 5:53 ` Viresh Kumar
2016-01-22 7:19 ` [PATCH v6 3/5] cpufreq: powernv/tracing: Add powernv_throttle tracepoint Shilpasri G Bhat
2016-01-22 7:19 ` [PATCH v6 4/5] cpufreq: powernv: Replace pr_info with trace print for throttle event Shilpasri G Bhat
2016-01-25 5:58 ` Viresh Kumar
2016-01-22 7:19 ` [PATCH v6 5/5] cpufreq: powernv: Add sysfs attributes to show throttle stats Shilpasri G Bhat
2016-01-23 8:40 ` Balbir Singh
2016-01-25 6:46 ` Shilpasri G Bhat
2016-01-25 5:43 ` [v6, " Michael Ellerman
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