From: Russell King - ARM Linux <linux@arm.linux.org.uk>
To: Marc Gonzalez <marc_gonzalez@sigmadesigns.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Daniel Lezcano <daniel.lezcano@linaro.org>,
LKML <linux-kernel@vger.kernel.org>,
Mans Rullgard <mans@mansr.com>,
Viresh Kumar <viresh.kumar@linaro.org>,
Nicolas Pitre <nico@linaro.org>, Tony Lindgren <tony@atomide.com>,
Sebastian Frias <sebastian_frias@sigmadesigns.com>
Subject: Re: [PATCH] clocksource: Store reg field within struct clocksource
Date: Wed, 18 Nov 2015 17:21:15 +0000 [thread overview]
Message-ID: <20151118172114.GS8644@n2100.arm.linux.org.uk> (raw)
In-Reply-To: <564C8086.80804@sigmadesigns.com>
On Wed, Nov 18, 2015 at 02:43:34PM +0100, Marc Gonzalez wrote:
> Since 'struct clocksource' is ____cacheline_aligned, gcc must insert
> a lot of padding between reg and clksrc in 'struct clocksource_mmio'
> (for example, L1_CACHE_BYTES = 64 on ARMv7).
>
> Storing reg within 'struct clocksource' removes unnecessary padding,
> and reg can then be grouped with other hot data. A nice side-effect
> of this patch is making container_of() unnecessary, which makes the
> code a bit simpler.
>
> On 32-bit platforms, reg fits in the padding between read and mask,
> meaning no downside from storing it there.
Just swap the order of 'reg' and 'clksrc'.
--
FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up
according to speedtest.net.
next prev parent reply other threads:[~2015-11-18 17:21 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-18 13:43 [PATCH] clocksource: Store reg field within struct clocksource Marc Gonzalez
2015-11-18 13:51 ` Måns Rullgård
2015-11-18 17:21 ` Russell King - ARM Linux [this message]
2015-11-19 9:27 ` Marc Gonzalez
2015-11-19 10:33 ` Russell King - ARM Linux
2015-11-19 10:36 ` Thomas Gleixner
2015-11-19 10:40 ` Russell King - ARM Linux
2015-11-19 10:33 ` Thomas Gleixner
2015-11-19 10:36 ` Russell King - ARM Linux
2015-11-19 10:42 ` Thomas Gleixner
2015-11-19 11:08 ` Russell King - ARM Linux
2015-11-19 11:14 ` Thomas Gleixner
2015-11-19 12:26 ` Marc Gonzalez
2015-11-19 13:57 ` Thomas Gleixner
2015-11-24 12:36 ` Marc Gonzalez
2015-11-25 21:33 ` [tip:timers/core] timekeeping: Lift clocksource cacheline restriction tip-bot for Thomas Gleixner
2015-11-19 10:55 ` [PATCH] clocksource: Store reg field within struct clocksource Marc Gonzalez
2015-11-19 11:21 ` Russell King - ARM Linux
2015-11-19 12:41 ` Marc Gonzalez
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