[RFC patch 02/15] get_cycles() : x86 HAVE_GET_CYCLES

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

Signed-off-by: Mathieu Desnoyers <redacted>
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 <redacted>
CC: Thomas Gleixner <redacted>
CC: Steven Rostedt <rostedt@goodmis.org>
CC: linux-arch@vger.kernel.org
---
 arch/x86/Kconfig      |    1 +
 include/asm-x86/tsc.h |   12 ++++++++++++
 2 files changed, 13 insertions(+)

Index: linux-2.6-lttng/arch/x86/Kconfig
===================================================================

--- linux-2.6-lttng.orig/arch/x86/Kconfig	2008-10-16 13:07:04.000000000 -0400
+++ linux-2.6-lttng/arch/x86/Kconfig	2008-10-16 13:07:12.000000000 -0400

@@ -19,6 +19,7 @@ config X86_64
 config X86
 	def_bool y
 	select HAVE_UNSTABLE_SCHED_CLOCK
+	select HAVE_GET_CYCLES
 	select HAVE_IDE
 	select HAVE_OPROFILE
 	select HAVE_IOREMAP_PROT

Index: linux-2.6-lttng/include/asm-x86/tsc.h
===================================================================

--- linux-2.6-lttng.orig/include/asm-x86/tsc.h	2008-10-16 13:07:04.000000000 -0400
+++ linux-2.6-lttng/include/asm-x86/tsc.h	2008-10-16 13:07:24.000000000 -0400

@@ -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
Computer Engineering Ph.D. Student, Ecole Polytechnique de Montreal
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F  BA06 3F25 A8FE 3BAE 9A68