From c73deb6aecda2955716f31572516f09d930ef450 Mon Sep 17 00:00:00 2001 From: Adrian Hunter Date: Fri, 28 Jun 2013 16:22:18 +0300 Subject: perf/x86: Add ability to calculate TSC from perf sample timestamps For modern CPUs, perf clock is directly related to TSC. TSC can be calculated from perf clock and vice versa using a simple calculation. Two of the three componenets of that calculation are already exported in struct perf_event_mmap_page. This patch exports the third. Signed-off-by: Adrian Hunter Signed-off-by: Peter Zijlstra Cc: "H. Peter Anvin" Link: http://lkml.kernel.org/r/1372425741-1676-3-git-send-email-adrian.hunter@intel.com Signed-off-by: Ingo Molnar --- arch/x86/kernel/tsc.c | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'arch/x86/kernel/tsc.c') diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c index 6ff49247edf..930e5d48f56 100644 --- a/arch/x86/kernel/tsc.c +++ b/arch/x86/kernel/tsc.c @@ -89,6 +89,12 @@ int check_tsc_unstable(void) } EXPORT_SYMBOL_GPL(check_tsc_unstable); +int check_tsc_disabled(void) +{ + return tsc_disabled; +} +EXPORT_SYMBOL_GPL(check_tsc_disabled); + #ifdef CONFIG_X86_TSC int __init notsc_setup(char *str) { -- cgit v1.2.3-70-g09d2