Commit-ID: f24ade3a3332811a512ed3b6c6aa69486719b1d8
Gitweb: http://git.kernel.org/tip/f24ade3a3332811a512ed3b6c6aa69486719b1d8
Author: "Ingo Molnar" <mingo@xxxxxxx>
AuthorDate: Tue, 10 Mar 2009 19:02:30 +0100
Commit: Ingo Molnar <mingo@xxxxxxx>
CommitDate: Tue, 10 Mar 2009 19:02:30 +0100
x86, sched_clock(): mark variables read-mostly
Impact: micro-optimization
There's a number of variables in the sched_clock() path that are
in .data/.bss - but not marked __read_mostly. This creates the
danger of accidental false cacheline sharing with some other,
write-often variable.
So mark them __read_mostly.
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
---
arch/x86/kernel/tsc.c | 9 +++++----
1 files changed, 5 insertions(+), 4 deletions(-)
diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c
index 599e581..9c8b715 100644
--- a/arch/x86/kernel/tsc.c
+++ b/arch/x86/kernel/tsc.c
@@ -17,20 +17,21 @@
#include <asm/delay.h>
#include <asm/hypervisor.h>
-unsigned int cpu_khz; /* TSC clocks / usec, not used here */
+unsigned int __read_mostly cpu_khz; /* TSC clocks / usec, not used here */
EXPORT_SYMBOL(cpu_khz);
-unsigned int tsc_khz;
+
+unsigned int __read_mostly tsc_khz;
EXPORT_SYMBOL(tsc_khz);
/*
* TSC can be unstable due to cpufreq or due to unsynced TSCs
*/
-static int tsc_unstable;
+static int __read_mostly tsc_unstable;
/* native_sched_clock() is called before tsc_init(), so
we must start with the TSC soft disabled to prevent
erroneous rdtsc usage on !cpu_has_tsc processors */
-static int tsc_disabled = -1;
+static int __read_mostly tsc_disabled = -1;
static int tsc_clocksource_reliable;
/*
--
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