perf/x86/intel: Account interrupts for PEBS errors
[ Upstream commit 475113d937
]
It's possible to set up PEBS events to get only errors and not
any data, like on SNB-X (model 45) and IVB-EP (model 62)
via 2 perf commands running simultaneously:
taskset -c 1 ./perf record -c 4 -e branches:pp -j any -C 10
This leads to a soft lock up, because the error path of the
intel_pmu_drain_pebs_nhm() does not account event->hw.interrupt
for error PEBS interrupts, so in case you're getting ONLY
errors you don't have a way to stop the event when it's over
the max_samples_per_tick limit:
NMI watchdog: BUG: soft lockup - CPU#22 stuck for 22s! [perf_fuzzer:5816]
...
RIP: 0010:[<ffffffff81159232>] [<ffffffff81159232>] smp_call_function_single+0xe2/0x140
...
Call Trace:
? trace_hardirqs_on_caller+0xf5/0x1b0
? perf_cgroup_attach+0x70/0x70
perf_install_in_context+0x199/0x1b0
? ctx_resched+0x90/0x90
SYSC_perf_event_open+0x641/0xf90
SyS_perf_event_open+0x9/0x10
do_syscall_64+0x6c/0x1f0
entry_SYSCALL64_slow_path+0x25/0x25
Add perf_event_account_interrupt() which does the interrupt
and frequency checks and call it from intel_pmu_drain_pebs_nhm()'s
error path.
We keep the pending_kill and pending_wakeup logic only in the
__perf_event_overflow() path, because they make sense only if
there's any data to deliver.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vince@deater.net>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: http://lkml.kernel.org/r/1482931866-6018-2-git-send-email-jolsa@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
steinar/wifi_calib_4_9_kernel
parent
72232a3bc5
commit
a88ff235e8
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@ -1389,9 +1389,13 @@ static void intel_pmu_drain_pebs_nhm(struct pt_regs *iregs)
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continue;
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/* log dropped samples number */
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if (error[bit])
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if (error[bit]) {
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perf_log_lost_samples(event, error[bit]);
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if (perf_event_account_interrupt(event))
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x86_pmu_stop(event, 0);
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}
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if (counts[bit]) {
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__intel_pmu_pebs_event(event, iregs, base,
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top, bit, counts[bit]);
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@ -1259,6 +1259,7 @@ extern void perf_event_disable(struct perf_event *event);
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extern void perf_event_disable_local(struct perf_event *event);
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extern void perf_event_disable_inatomic(struct perf_event *event);
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extern void perf_event_task_tick(void);
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extern int perf_event_account_interrupt(struct perf_event *event);
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#else /* !CONFIG_PERF_EVENTS: */
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static inline void *
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perf_aux_output_begin(struct perf_output_handle *handle,
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@ -7088,25 +7088,12 @@ static void perf_log_itrace_start(struct perf_event *event)
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perf_output_end(&handle);
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}
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/*
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* Generic event overflow handling, sampling.
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*/
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static int __perf_event_overflow(struct perf_event *event,
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int throttle, struct perf_sample_data *data,
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struct pt_regs *regs)
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static int
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__perf_event_account_interrupt(struct perf_event *event, int throttle)
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{
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int events = atomic_read(&event->event_limit);
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struct hw_perf_event *hwc = &event->hw;
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u64 seq;
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int ret = 0;
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/*
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* Non-sampling counters might still use the PMI to fold short
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* hardware counters, ignore those.
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*/
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if (unlikely(!is_sampling_event(event)))
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return 0;
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u64 seq;
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seq = __this_cpu_read(perf_throttled_seq);
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if (seq != hwc->interrupts_seq) {
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@ -7134,6 +7121,34 @@ static int __perf_event_overflow(struct perf_event *event,
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perf_adjust_period(event, delta, hwc->last_period, true);
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}
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return ret;
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}
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int perf_event_account_interrupt(struct perf_event *event)
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{
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return __perf_event_account_interrupt(event, 1);
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}
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/*
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* Generic event overflow handling, sampling.
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*/
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static int __perf_event_overflow(struct perf_event *event,
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int throttle, struct perf_sample_data *data,
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struct pt_regs *regs)
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{
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int events = atomic_read(&event->event_limit);
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int ret = 0;
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/*
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* Non-sampling counters might still use the PMI to fold short
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* hardware counters, ignore those.
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*/
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if (unlikely(!is_sampling_event(event)))
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return 0;
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ret = __perf_event_account_interrupt(event, throttle);
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/*
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* XXX event_limit might not quite work as expected on inherited
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* events
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