From: Christoph Lameter <clameter@engr.sgi.com>
Date: Thu, 2 Mar 2006 10:54:35 +0000 (-0800)
Subject: [PATCH] time_interpolator: Use readq_relaxed() instead of readq().
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=685db65e422bfa523b8a9dacb5a658b42b254f05;p=GitHub%2Fmt8127%2Fandroid_kernel_alcatel_ttab.git

[PATCH] time_interpolator: Use readq_relaxed() instead of readq().

On some platforms readq performs additional work to make sure I/O is done
in a coherent way.  This is not needed for time retrieval as done by the
time interpolator.  So we can use readq_relaxed instead which will improve
performance.

It affects sparc64 and ia64 only.  Apparently it makes a significant
difference on ia64.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Cc: john stultz <johnstul@us.ibm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
---

diff --git a/kernel/timer.c b/kernel/timer.c
index fe3a9a9f8328..fc6646fd5aab 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -1351,10 +1351,10 @@ static inline u64 time_interpolator_get_cycles(unsigned int src)
 			return x();
 
 		case TIME_SOURCE_MMIO64	:
-			return readq((void __iomem *) time_interpolator->addr);
+			return readq_relaxed((void __iomem *)time_interpolator->addr);
 
 		case TIME_SOURCE_MMIO32	:
-			return readl((void __iomem *) time_interpolator->addr);
+			return readl_relaxed((void __iomem *)time_interpolator->addr);
 
 		default: return get_cycles();
 	}