From dd30ac327481f1663b6526fa9fa078569188b7cc Mon Sep 17 00:00:00 2001
From: Horst Hartmann <horsth@linux.vnet.ibm.com>
Date: Thu, 17 Feb 2011 13:13:59 +0100
Subject: [PATCH] [S390] net: provide architecture specific NET_SKB_PAD
NET_SKB_PAD has been increased from 32 to 64 and later to
max(32, L1_CACHE_BYTES). This led to a 25% throughput decrease for
streaming workloads accompanied by a 37% CPU cost increase on s390.
Define a architecture specific NET_SKB_PAD with the old value of 32.
Signed-off-by: Horst Hartmann <horsth@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
---
arch/s390/include/asm/cache.h | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/s390/include/asm/cache.h b/arch/s390/include/asm/cache.h
index 24aafa68b6436..2a30d5ac0667a 100644
--- a/arch/s390/include/asm/cache.h
+++ b/arch/s390/include/asm/cache.h
@@ -13,6 +13,7 @@
#define L1_CACHE_BYTES 256
#define L1_CACHE_SHIFT 8
+#define NET_SKB_PAD 32
#define __read_mostly __attribute__((__section__(".data..read_mostly")))
--
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