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authorIngo Molnar <mingo@kernel.org>2016-07-10 20:58:36 +0200
committerIngo Molnar <mingo@kernel.org>2016-07-10 20:58:36 +0200
commit44530d588e142a96cf0cd345a7cb8911c4f88720 (patch)
treef1b2a9d46904fd3479c320267691ee89d172b3dc /arch
parent46866b59dfbe9bf99bb1323ce1f3fd2073a81aa3 (diff)
downloadlinux-44530d588e142a96cf0cd345a7cb8911c4f88720.tar.bz2
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 <ak@linux.intel.com> > 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 <eranian@google.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Vince Weaver <vincent.weaver@maine.edu> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/kernel/apic/hw_nmi.c8
1 files changed, 0 insertions, 8 deletions
diff --git a/arch/x86/kernel/apic/hw_nmi.c b/arch/x86/kernel/apic/hw_nmi.c
index 016f4263fad4..7788ce643bf4 100644
--- a/arch/x86/kernel/apic/hw_nmi.c
+++ b/arch/x86/kernel/apic/hw_nmi.c
@@ -18,16 +18,8 @@
#include <linux/nmi.h>
#include <linux/module.h>
#include <linux/delay.h>
-#include <linux/perf_event.h>
#ifdef CONFIG_HARDLOCKUP_DETECTOR
-int hw_nmi_get_event(void)
-{
- if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL)
- return PERF_COUNT_HW_REF_CPU_CYCLES;
- return PERF_COUNT_HW_CPU_CYCLES;
-}
-
u64 hw_nmi_get_sample_period(int watchdog_thresh)
{
return (u64)(cpu_khz) * 1000 * watchdog_thresh;