[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 fe3a9a9..fc6646f 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -1351,10 +1351,10 @@
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();
}