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[v2,5/6] i.MX: system.c: Tweak prefetch settings for performance

Message ID 1465954193-5894-6-git-send-email-andrew.smirnov@gmail.com (mailing list archive)
State New, archived
Headers show

Commit Message

Andrey Smirnov June 15, 2016, 1:29 a.m. UTC 
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(-)
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Patch

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);
 	}