Revert "perf/x86/intel, watchdog: Switch NMI watchdog to ref cycles on x86"

This reverts commit 2c95afc1e83d93fac3be6923465e1753c2c53b0a.

Stephane reported the following regression:

 > Since Andi added:
 >
 > commit 2c95afc1e83d93fac3be6923465e1753c2c53b0a
 > Author: Andi Kleen <[email protected]>
 > Date:   Thu Jun 9 06:14:38 2016 -0700
 >
 >    perf/x86/intel, watchdog: Switch NMI watchdog to ref cycles on x86
 >
 > $ perf stat -e ref-cycles ls
 >   <not counted> ....
 >
 > fails systematically because the ref-cycles is now used by the
 > watchdog and given this is a system-wide pinned event, it monopolizes
 > the fixed counter 2 which is the only counter able to measure this event.

Since the next merge window is near, fix the regression for now
by reverting the commit.

Reported-by: Stephane Eranian <[email protected]>
Cc: Andi Kleen <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Vince Weaver <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
Signed-off-by: Ingo Molnar <[email protected]>

1 files changed, 0 insertions, 1 deletions

diff --git a/include/linux/nmi.h b/include/linux/nmi.h
index 79858af27209..4630eeae18e0 100644
--- a/include/linux/nmi.h
+++ b/include/linux/nmi.h
@@ -66,7 +66,6 @@ static inline bool trigger_allbutself_cpu_backtrace(void)
 
 #ifdef CONFIG_LOCKUP_DETECTOR
 u64 hw_nmi_get_sample_period(int watchdog_thresh);
-int hw_nmi_get_event(void);
 extern int nmi_watchdog_enabled;
 extern int soft_watchdog_enabled;
 extern int watchdog_user_enabled;