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From: Brad Mouring <brad.mouring-acOepvfBmUk@public.gmane.org>
To: linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org
Cc: devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	Russell King <rmk+kernel-lFZ/pmaqli7XmaaqVzeoHQ@public.gmane.org>
Subject: [PATCH 0/2] Control PL310 pwr_ctrl register through DT
Date: Tue, 23 Feb 2016 16:03:37 -0600	[thread overview]
Message-ID: <1456265019-23900-1-git-send-email-brad.mouring@ni.com> (raw)


During some performance-oriented benchmarking on a Cortex A9
platform, a slight performance degradation was noted on datasets
that spanned into the L2 cache (<10%). This performance hit was
minor, but it prompted investigation into the cause.

One difference in the actual PL310 configuration that was concerning
was the enabling of two PM-related changes: Dynamic Clock Gating
and Standby Mode Enabling. As the kernel being tested was patched
and configured to use the PREEMPT_RT patchset, it was desired to
disable these settings for our use-case since anything PM can
(and usually does) impact determinism.

Making these changes resulted in a modest performance improvement
and those wonderful warm-n-fuzzies regarding determinism and enabling
system control without needing to change the kernel.

In the following set, there's the actual change to control these
features given DT presence of a couple of new bindings and the
documenation to accompany those changes. Thanks!
--
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             reply	other threads:[~2016-02-23 22:03 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-02-23 22:03 Brad Mouring [this message]
     [not found] ` <1456265019-23900-1-git-send-email-brad.mouring-acOepvfBmUk@public.gmane.org>
2016-02-23 22:03   ` [PATCH 1/2] pl2x0: Add OF control of cache power management Brad Mouring
2016-02-23 22:03   ` [PATCH 2/2] Documentation: devicetree: Add PL310 PM bindings Brad Mouring
     [not found]     ` <1456265019-23900-3-git-send-email-brad.mouring-acOepvfBmUk@public.gmane.org>
2016-02-24  1:33       ` Rob Herring
2016-02-29 16:01   ` [PATCH 1/2] pl2x0: Add OF control of cache power management Brad Mouring
     [not found]     ` <1456761716-10174-1-git-send-email-brad.mouring-acOepvfBmUk@public.gmane.org>
2016-02-29 16:01       ` [PATCH 2/2] Documentation: devicetree: Add PL310 PM bindings Brad Mouring

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