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From: rric@kernel.org (Robert Richter)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] arm64: Increase the max granular size
Date: Tue, 22 Sep 2015 19:59:48 +0200	[thread overview]
Message-ID: <1442944788-17254-1-git-send-email-rric@kernel.org> (raw)

From: Tirumalesh Chalamarla <tchalamarla@cavium.com>

Increase the standard cacheline size to avoid having locks in the same
cacheline.

Cavium's ThunderX core implements cache lines of 128 byte size. With
current granulare size of 64 bytes (L1_CACHE_SHIFT=6) two locks could
share the same cache line leading a performance degradation.
Increasing the size fixes that.

Increasing the size has no negative impact to cache invalidation on
systems with a smaller cache line. There is an impact on memory usage,
but that's not too important for arm64 use cases.

Signed-off-by: Tirumalesh Chalamarla <tchalamarla@cavium.com>
Signed-off-by: Robert Richter <rrichter@cavium.com>
---
 arch/arm64/include/asm/cache.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/include/asm/cache.h b/arch/arm64/include/asm/cache.h
index bde449936e2f..5082b30bc2c0 100644
--- a/arch/arm64/include/asm/cache.h
+++ b/arch/arm64/include/asm/cache.h
@@ -18,7 +18,7 @@
 
 #include <asm/cachetype.h>
 
-#define L1_CACHE_SHIFT		6
+#define L1_CACHE_SHIFT		7
 #define L1_CACHE_BYTES		(1 << L1_CACHE_SHIFT)
 
 /*
-- 
2.1.1

             reply	other threads:[~2015-09-22 17:59 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-09-22 17:59 Robert Richter [this message]
2015-09-22 18:29 ` [PATCH] arm64: Increase the max granular size Will Deacon
2015-09-25 14:45   ` Robert Richter
2015-09-25 16:31     ` Tirumalesh Chalamarla
2015-10-10 17:39 ` Timur Tabi
2015-10-12  9:16   ` Will Deacon
2015-10-16 19:57 ` Timur Tabi
2015-10-28 19:09 ` Catalin Marinas
     [not found]   ` <CAMuHMdWQygbxMXoOsbwek6DzZcr7J-C23VCK4ubbgUr+zj=giw@mail.gmail.com>
2015-11-03 12:05     ` Catalin Marinas
2015-11-03 14:38       ` Catalin Marinas
2015-11-03 14:55         ` Geert Uytterhoeven
2015-11-03 18:50           ` Catalin Marinas
2015-11-03 23:33             ` Christoph Lameter
2015-11-04 12:36               ` Catalin Marinas
2015-11-04 13:53                 ` Christoph Lameter
2015-11-04 14:54                   ` Catalin Marinas
2015-11-04 15:28                     ` Christoph Lameter
2015-11-04 15:39                       ` Catalin Marinas
2015-11-05  4:31                         ` Joonsoo Kim
2015-11-05 11:50                           ` [PATCH] mm: slab: Only move management objects off-slab for sizes larger than KMALLOC_MIN_SIZE Catalin Marinas
2015-11-05 13:31                             ` Andrew Morton
2015-11-05 16:08                               ` Catalin Marinas
2015-11-06 13:00                                 ` Geert Uytterhoeven
2015-11-05 17:39                             ` Christoph Lameter
2015-11-05  4:40 ` [PATCH] arm64: Increase the max granular size Joonsoo Kim
2015-11-05 10:32   ` Catalin Marinas
2015-11-05 11:45     ` Joonsoo Kim
2015-11-05 12:17       ` Catalin Marinas
2015-11-09  7:41         ` Joonsoo Kim
2015-11-09 18:36           ` Catalin Marinas
2015-11-10  0:19             ` Joonsoo Kim

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