[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>

1 files changed, 2 insertions, 2 deletions

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();
         }