Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759451AbcLPIJE (ORCPT ); Fri, 16 Dec 2016 03:09:04 -0500 Received: from mx1.redhat.com ([209.132.183.28]:42168 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753951AbcLPIJD (ORCPT ); Fri, 16 Dec 2016 03:09:03 -0500 Date: Fri, 16 Dec 2016 09:07:45 +0100 From: Jiri Olsa To: Peter Zijlstra Cc: kbuild-all@01.org, Peter Zijlstra , kbuild test robot , Andi Kleen , lkml , Alexander Shishkin , Vince Weaver , Ingo Molnar Subject: [PATCHv3] perf/x86/intel: Account interrupts for PEBS errors Message-ID: <20161216080745.GA6109@krava> References: <20161215154356.GB9173@krava> <201612160736.BAd9BYGY%fengguang.wu@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <201612160736.BAd9BYGY%fengguang.wu@intel.com> User-Agent: Mutt/1.7.1 (2016-10-04) X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.27]); Fri, 16 Dec 2016 08:07:48 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6247 Lines: 193 On Fri, Dec 16, 2016 at 07:41:04AM +0800, kbuild test robot wrote: > Hi Jiri, > > [auto build test WARNING on tip/perf/core] > [also build test WARNING on v4.9 next-20161215] > [if your patch is applied to the wrong git tree, please drop us a note to help improve the system] > > url: https://github.com/0day-ci/linux/commits/Jiri-Olsa/perf-x86-intel-Account-interrupts-for-PEBS-errors/20161216-042644 > config: x86_64-randconfig-a0-12160640 (attached as .config) > compiler: gcc-4.4 (Debian 4.4.7-8) 4.4.7 > reproduce: > # save the attached .config to linux build tree > make ARCH=x86_64 > > All warnings (new ones prefixed by >>): > > kernel/events/core.c: In function '__perf_event_overflow': > >> kernel/events/core.c:7086: warning: unused variable 'hwc' > kernel/events/core.o: warning: objtool: perf_try_init_event()+0x43: function has unreachable instruction > > vim +/hwc +7086 kernel/events/core.c > > 7070 } > 7071 > 7072 int perf_event_account_interrupt(struct perf_event *event) > 7073 { > 7074 return __perf_event_account_interrupt(event, 1); > 7075 } > 7076 > 7077 /* > 7078 * Generic event overflow handling, sampling. > 7079 */ > 7080 > 7081 static int __perf_event_overflow(struct perf_event *event, > 7082 int throttle, struct perf_sample_data *data, > 7083 struct pt_regs *regs) > 7084 { > 7085 int events = atomic_read(&event->event_limit); > > 7086 struct hw_perf_event *hwc = &event->hw; > 7087 int ret = 0; > 7088 ugh, I guess I'm too used to the perf tool to fail build on unused variable :-\ v3 attached thanks, jirka --- It's possible to setup PEBS events and get only errors and not a single 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 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 the event is not eventually stopped when it gets over the max_samples_per_tick limit. NMI watchdog: BUG: soft lockup - CPU#22 stuck for 22s! [perf_fuzzer:5816] ... task: ffff880273148000 task.stack: ffffc90002d58000 RIP: 0010:[] [] smp_call_function_single+0xe2/0x140 RSP: 0018:ffffc90002d5bd60 EFLAGS: 00000202 ... 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 Adding perf_event_account_interrupt with event's interrupt and frequency checks and calling it from drain_pebs's error path. Keeping pending_kill and pending_wakeup check up logic only in __perf_event_overflow path, because they make sense only in case if there's any data to deliver. Signed-off-by: Jiri Olsa --- arch/x86/events/intel/ds.c | 6 +++++- include/linux/perf_event.h | 1 + kernel/events/core.c | 46 ++++++++++++++++++++++++++++++---------------- 3 files changed, 36 insertions(+), 17 deletions(-) diff --git a/arch/x86/events/intel/ds.c b/arch/x86/events/intel/ds.c index be202390bbd3..9dfeeeca0ea8 100644 --- a/arch/x86/events/intel/ds.c +++ b/arch/x86/events/intel/ds.c @@ -1389,9 +1389,13 @@ static void intel_pmu_drain_pebs_nhm(struct pt_regs *iregs) continue; /* log dropped samples number */ - if (error[bit]) + if (error[bit]) { perf_log_lost_samples(event, error[bit]); + if (perf_event_account_interrupt(event)) + x86_pmu_stop(event, 0); + } + if (counts[bit]) { __intel_pmu_pebs_event(event, iregs, base, top, bit, counts[bit]); diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index 4741ecdb9817..78ed8105e64d 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -1259,6 +1259,7 @@ extern void perf_event_disable(struct perf_event *event); extern void perf_event_disable_local(struct perf_event *event); extern void perf_event_disable_inatomic(struct perf_event *event); extern void perf_event_task_tick(void); +extern int perf_event_account_interrupt(struct perf_event *event); #else /* !CONFIG_PERF_EVENTS: */ static inline void * perf_aux_output_begin(struct perf_output_handle *handle, diff --git a/kernel/events/core.c b/kernel/events/core.c index 02c8421f8c01..bb24d5abc40a 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -7034,25 +7034,11 @@ static void perf_log_itrace_start(struct perf_event *event) perf_output_end(&handle); } -/* - * Generic event overflow handling, sampling. - */ - -static int __perf_event_overflow(struct perf_event *event, - int throttle, struct perf_sample_data *data, - struct pt_regs *regs) +static int __perf_event_account_interrupt(struct perf_event *event, int throttle) { - int events = atomic_read(&event->event_limit); struct hw_perf_event *hwc = &event->hw; - u64 seq; int ret = 0; - - /* - * Non-sampling counters might still use the PMI to fold short - * hardware counters, ignore those. - */ - if (unlikely(!is_sampling_event(event))) - return 0; + u64 seq; seq = __this_cpu_read(perf_throttled_seq); if (seq != hwc->interrupts_seq) { @@ -7080,6 +7066,34 @@ static int __perf_event_overflow(struct perf_event *event, perf_adjust_period(event, delta, hwc->last_period, true); } + return ret; +} + +int perf_event_account_interrupt(struct perf_event *event) +{ + return __perf_event_account_interrupt(event, 1); +} + +/* + * Generic event overflow handling, sampling. + */ + +static int __perf_event_overflow(struct perf_event *event, + int throttle, struct perf_sample_data *data, + struct pt_regs *regs) +{ + int events = atomic_read(&event->event_limit); + int ret = 0; + + /* + * Non-sampling counters might still use the PMI to fold short + * hardware counters, ignore those. + */ + if (unlikely(!is_sampling_event(event))) + return 0; + + ret = __perf_event_account_interrupt(event, throttle); + /* * XXX event_limit might not quite work as expected on inherited * events -- 2.7.4