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From: Andrey Smirnov <andrew.smirnov@gmail.com>
To: linux-arm-kernel@lists.infradead.org
Cc: Russell King <linux@arm.linux.org.uk>,
	Shawn Guo <shawnguo@kernel.org>,
	Sascha Hauer <kernel@pengutronix.de>,
	Arnd Bergmann <arnd@arndb.de>,
	linux-kernel@vger.kernel.org,
	Andrey Smirnov <andrew.smirnov@gmail.com>
Subject: [PATCH v2 5/6] i.MX: system.c: Tweak prefetch settings for performance
Date: Tue, 14 Jun 2016 18:29:52 -0700	[thread overview]
Message-ID: <1465954193-5894-6-git-send-email-andrew.smirnov@gmail.com> (raw)
In-Reply-To: <1465954193-5894-1-git-send-email-andrew.smirnov@gmail.com>

Update Prefetch Control Register settings to match that of Freescale's
Linux tree. As the commit e3addf1b773964eac7f797e8538c69481be4279c
states (author Nitin Garg):

"... set Prefetch offset to 15, since it improves memcpy performance by
35%. Don't enable Incr double Linefill enable since it adversely affects
memcpy performance by about 32MB/s and reads by 90MB/s. Tested with 4K
to 16MB sized src and dst aligned buffer..."

Those results are also corroborated by our own testing.

Tested-by: Chris Healy <cphealy@gmail.com>
Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
---
 arch/arm/mach-imx/system.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/arch/arm/mach-imx/system.c b/arch/arm/mach-imx/system.c
index f0a9787..9ea01e3 100644
--- a/arch/arm/mach-imx/system.c
+++ b/arch/arm/mach-imx/system.c
@@ -111,8 +111,12 @@ void __init imx_init_l2cache(void)
 		val = readl_relaxed(l2x0_base + L310_PREFETCH_CTRL);
 		val |=  L310_PREFETCH_CTRL_DBL_LINEFILL |
 		        L310_PREFETCH_CTRL_INSTR_PREFETCH |
-			L310_PREFETCH_CTRL_DATA_PREFETCH |
-			L310_PREFETCH_CTRL_DBL_LINEFILL_INCR;
+			L310_PREFETCH_CTRL_DATA_PREFETCH;
+
+		/* Set perfetch offset to improve performance */
+		val &= ~L310_PREFETCH_CTRL_OFFSET_MASK;
+		val |= 15;
+
 		writel_relaxed(val, l2x0_base + L310_PREFETCH_CTRL);
 	}
 
-- 
2.5.5

WARNING: multiple messages have this Message-ID (diff)
From: andrew.smirnov@gmail.com (Andrey Smirnov)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2 5/6] i.MX: system.c: Tweak prefetch settings for performance
Date: Tue, 14 Jun 2016 18:29:52 -0700	[thread overview]
Message-ID: <1465954193-5894-6-git-send-email-andrew.smirnov@gmail.com> (raw)
In-Reply-To: <1465954193-5894-1-git-send-email-andrew.smirnov@gmail.com>

Update Prefetch Control Register settings to match that of Freescale's
Linux tree. As the commit e3addf1b773964eac7f797e8538c69481be4279c
states (author Nitin Garg):

"... set Prefetch offset to 15, since it improves memcpy performance by
35%. Don't enable Incr double Linefill enable since it adversely affects
memcpy performance by about 32MB/s and reads by 90MB/s. Tested with 4K
to 16MB sized src and dst aligned buffer..."

Those results are also corroborated by our own testing.

Tested-by: Chris Healy <cphealy@gmail.com>
Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
---
 arch/arm/mach-imx/system.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/arch/arm/mach-imx/system.c b/arch/arm/mach-imx/system.c
index f0a9787..9ea01e3 100644
--- a/arch/arm/mach-imx/system.c
+++ b/arch/arm/mach-imx/system.c
@@ -111,8 +111,12 @@ void __init imx_init_l2cache(void)
 		val = readl_relaxed(l2x0_base + L310_PREFETCH_CTRL);
 		val |=  L310_PREFETCH_CTRL_DBL_LINEFILL |
 		        L310_PREFETCH_CTRL_INSTR_PREFETCH |
-			L310_PREFETCH_CTRL_DATA_PREFETCH |
-			L310_PREFETCH_CTRL_DBL_LINEFILL_INCR;
+			L310_PREFETCH_CTRL_DATA_PREFETCH;
+
+		/* Set perfetch offset to improve performance */
+		val &= ~L310_PREFETCH_CTRL_OFFSET_MASK;
+		val |= 15;
+
 		writel_relaxed(val, l2x0_base + L310_PREFETCH_CTRL);
 	}
 
-- 
2.5.5

  parent reply	other threads:[~2016-06-15  1:30 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-06-15  1:29 [PATCH v2 0/6] i.MX L2-cache code cleanups and performance tweaks Andrey Smirnov
2016-06-15  1:29 ` Andrey Smirnov
2016-06-15  1:29 ` [PATCH v2 1/6] i.MX: system.c: Convert goto to if statement Andrey Smirnov
2016-06-15  1:29   ` Andrey Smirnov
2016-06-15  1:29 ` [PATCH v2 2/6] i.MX: system.c: Remove redundant errata 752271 code Andrey Smirnov
2016-06-15  1:29   ` Andrey Smirnov
2016-06-15  1:29 ` [PATCH v2 3/6] i.MX: system.c: Replace magic numbers Andrey Smirnov
2016-06-15  1:29   ` Andrey Smirnov
2016-06-15  6:18   ` Uwe Kleine-König
2016-06-15  6:18     ` Uwe Kleine-König
2016-06-16  2:00   ` Shawn Guo
2016-06-16  2:00     ` Shawn Guo
2016-06-15  1:29 ` [PATCH v2 4/6] ARM: cache-l2x0: Do not clear bit 23 in prefetch control register Andrey Smirnov
2016-06-15  1:29   ` Andrey Smirnov
2016-06-15  1:29 ` Andrey Smirnov [this message]
2016-06-15  1:29   ` [PATCH v2 5/6] i.MX: system.c: Tweak prefetch settings for performance Andrey Smirnov
2016-06-15  1:29 ` [PATCH v2 6/6] i.MX: Do not explicitly call l2x0_of_init() Andrey Smirnov
2016-06-15  1:29   ` Andrey Smirnov
2016-06-15 10:41   ` Arnd Bergmann
2016-06-15 10:41     ` Arnd Bergmann

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