[RFC patch 02/18] get_cycles() : x86 HAVE_GET_CYCLES

[Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>]

[-- Attachment #1: get-cycles-x86-have-get-cycles.patch --]
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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@polymtl.ca>
CC: David Miller <davem@davemloft.net>
CC: Linus Torvalds <torvalds@linux-foundation.org>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: Ingo Molnar <mingo@redhat.com>
CC: Peter Zijlstra <a.p.zijlstra@chello.nl>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Steven Rostedt <rostedt@goodmis.org>
CC: linux-arch@vger.kernel.org
---
 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	2008-11-07 00:06:06.000000000 -0500
+++ linux.trees.git/arch/x86/Kconfig	2008-11-07 00:09:33.000000000 -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	2008-10-30 20:22:50.000000000 -0400
+++ linux.trees.git/arch/x86/include/asm/tsc.h	2008-11-07 00:09:33.000000000 -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 tsc_khz;
+}
+
+static inline void get_cycles_barrier(void)
+{
+	rdtsc_barrier();
+}
+
 /*
  * Boot-time check whether the TSCs are synchronized across
  * all CPUs/cores:

-- 
Mathieu Desnoyers
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