From: linux@arm.linux.org.uk (Russell King - ARM Linux)
To: linux-arm-kernel@lists.infradead.org
Subject: [RFC PATCH] ARM: l2x0: avoid spinlock for sync op on pl310
Date: Tue, 11 Sep 2012 00:13:43 +0100 [thread overview]
Message-ID: <20120910231343.GE31998@n2100.arm.linux.org.uk> (raw)
In-Reply-To: <1347306334-781-1-git-send-email-robherring2@gmail.com>
On Mon, Sep 10, 2012 at 02:45:34PM -0500, Rob Herring wrote:
> From: Rob Herring <rob.herring@calxeda.com>
>
> The sync op is atomic on the pl310, so a spinlock is not needed. It can
> be a bottleneck for code paths with register accesses, so remove it.
> Removing it gives a 30% improvement to pktgen throughput on highbank.
>
> A similar spinlock removal was originally done by Catalin Marinas[1], but
> the spinlock part was dropped in the merged version. It is unclear why
> other than it was not a runtime selection. As every readl/writel causes a
> outer_sync, the sync function is likely the most critical.
See:
http://lists.arm.linux.org.uk/lurker/message/20110215.164340.dc0ec480.en.html
next prev parent reply other threads:[~2012-09-10 23:13 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-10 19:45 [RFC PATCH] ARM: l2x0: avoid spinlock for sync op on pl310 Rob Herring
2012-09-10 23:13 ` Russell King - ARM Linux [this message]
2012-09-17 13:59 ` [PATCH v2] ARM: l2x0: make background cache ops optional for clean and flush range Rob Herring
2012-09-17 19:47 ` Russell King - ARM Linux
2012-09-17 20:29 ` Rob Herring
2012-09-17 20:45 ` Catalin Marinas
2012-09-17 21:36 ` Rob Herring
2012-09-17 21:47 ` Russell King - ARM Linux
2012-09-18 2:43 ` Rob Herring
2012-09-18 8:21 ` Catalin Marinas
2012-09-18 12:00 ` Rob Herring
2012-09-17 22:31 ` Nicolas Pitre
2012-09-18 12:50 ` Rob Herring
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