[patch 02/17] get_cycles() : x86 HAVE_GET_CYCLES

From: Mathieu Desnoyers
Date: Wed Nov 26 2008 - 08:03:14 EST


This patch selects HAVE_GET_CYCLES and makes sure get_cycles_barrier() and
get_cycles_rate() are implemented.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxx>
CC: David Miller <davem@xxxxxxxxxxxxx>
CC: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
CC: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
CC: Ingo Molnar <mingo@xxxxxxxxxx>
CC: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
CC: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CC: Steven Rostedt <rostedt@xxxxxxxxxxx>
CC: linux-arch@xxxxxxxxxxxxxxx
---
arch/x86/Kconfig | 1 +
arch/x86/include/asm/tsc.h | 12 ++++++++++++
2 files changed, 13 insertions(+)

Index: linux.trees.git/arch/x86/Kconfig
===================================================================
--- linux.trees.git.orig/arch/x86/Kconfig 2008-11-26 05:46:29.000000000 -0500
+++ linux.trees.git/arch/x86/Kconfig 2008-11-26 06:48:49.000000000 -0500
@@ -20,6 +20,7 @@ config X86
def_bool y
select HAVE_AOUT if X86_32
select HAVE_UNSTABLE_SCHED_CLOCK
+ select HAVE_GET_CYCLES
select HAVE_IDE
select HAVE_OPROFILE
select HAVE_IOREMAP_PROT
Index: linux.trees.git/arch/x86/include/asm/tsc.h
===================================================================
--- linux.trees.git.orig/arch/x86/include/asm/tsc.h 2008-11-14 17:38:28.000000000 -0500
+++ linux.trees.git/arch/x86/include/asm/tsc.h 2008-11-26 06:48:49.000000000 -0500
@@ -50,6 +50,18 @@ extern void mark_tsc_unstable(char *reas
extern int unsynchronized_tsc(void);
int check_tsc_unstable(void);

+static inline cycles_t get_cycles_rate(void)
+{
+ if (check_tsc_unstable())
+ return 0;
+ return (cycles_t)tsc_khz * 1000;
+}
+
+static inline void get_cycles_barrier(void)
+{
+ rdtsc_barrier();
+}
+
/*
* Boot-time check whether the TSCs are synchronized across
* all CPUs/cores:

--
Mathieu Desnoyers
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68
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