diff options
| author | Ingo Molnar <mingo@kernel.org> | 2016-07-10 20:58:36 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2016-07-10 20:58:36 +0200 |
| commit | 44530d588e142a96cf0cd345a7cb8911c4f88720 (patch) | |
| tree | f1b2a9d46904fd3479c320267691ee89d172b3dc | |
| parent | 46866b59dfbe9bf99bb1323ce1f3fd2073a81aa3 (diff) | |
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>
| -rw-r--r-- | arch/x86/kernel/apic/hw_nmi.c | 8 | ||||
| -rw-r--r-- | include/linux/nmi.h | 1 | ||||
| -rw-r--r-- | kernel/watchdog.c | 7 |
3 files changed, 0 insertions, 16 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; 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; diff --git a/kernel/watchdog.c b/kernel/watchdog.c index 8dd30fcd91be..9acb29f280ec 100644 --- a/kernel/watchdog.c +++ b/kernel/watchdog.c @@ -315,12 +315,6 @@ static int is_softlockup(unsigned long touch_ts) #ifdef CONFIG_HARDLOCKUP_DETECTOR -/* Can be overriden by architecture */ -__weak int hw_nmi_get_event(void) -{ - return PERF_COUNT_HW_CPU_CYCLES; -} - static struct perf_event_attr wd_hw_attr = { .type = PERF_TYPE_HARDWARE, .config = PERF_COUNT_HW_CPU_CYCLES, @@ -610,7 +604,6 @@ static int watchdog_nmi_enable(unsigned int cpu) wd_attr = &wd_hw_attr; wd_attr->sample_period = hw_nmi_get_sample_period(watchdog_thresh); - wd_attr->config = hw_nmi_get_event(); /* Try to register using hardware perf events */ event = perf_event_create_kernel_counter(wd_attr, cpu, NULL, watchdog_overflow_callback, NULL); |