Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756844AbcLBVWx (ORCPT ); Fri, 2 Dec 2016 16:22:53 -0500 Received: from mga05.intel.com ([192.55.52.43]:13792 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750848AbcLBVUl (ORCPT ); Fri, 2 Dec 2016 16:20:41 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.33,288,1477983600"; d="scan'208";a="1093847497" From: kan.liang@intel.com To: peterz@infradead.org, mingo@redhat.com, acme@kernel.org, linux-kernel@vger.kernel.org Cc: alexander.shishkin@linux.intel.com, tglx@linutronix.de, namhyung@kernel.org, jolsa@kernel.org, adrian.hunter@intel.com, wangnan0@huawei.com, mark.rutland@arm.com, andi@firstfloor.org, Kan Liang Subject: [PATCH V2 03/13] perf/x86: output sampling overhead Date: Fri, 2 Dec 2016 16:19:11 -0500 Message-Id: <1480713561-6617-4-git-send-email-kan.liang@intel.com> X-Mailer: git-send-email 2.5.5 In-Reply-To: <1480713561-6617-1-git-send-email-kan.liang@intel.com> References: <1480713561-6617-1-git-send-email-kan.liang@intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2501 Lines: 91 From: Kan Liang On x86, NMI handler is the most important part which brings overhead for sampling. Adding a pmu specific overhead type PERF_PMU_SAMPLE_OVERHEAD for it. For other architectures which may don't have NMI, the overhead type can be reused. Signed-off-by: Kan Liang --- arch/x86/events/core.c | 17 ++++++++++++++++- arch/x86/events/perf_event.h | 2 ++ include/uapi/linux/perf_event.h | 1 + 3 files changed, 19 insertions(+), 1 deletion(-) diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c index 9d4bf3a..de40f96 100644 --- a/arch/x86/events/core.c +++ b/arch/x86/events/core.c @@ -1397,6 +1397,9 @@ static void x86_pmu_del(struct perf_event *event, int flags) perf_event_update_userpage(event); + if ((flags & PERF_EF_LOG) && cpuc->nmi_overhead.nr) + perf_log_overhead(event, PERF_PMU_SAMPLE_OVERHEAD, &cpuc->nmi_overhead); + do_del: if (x86_pmu.del) { /* @@ -1475,11 +1478,21 @@ void perf_events_lapic_init(void) apic_write(APIC_LVTPC, APIC_DM_NMI); } +static void +perf_calculate_nmi_overhead(u64 time) +{ + struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events); + + cpuc->nmi_overhead.nr++; + cpuc->nmi_overhead.time += time; +} + static int perf_event_nmi_handler(unsigned int cmd, struct pt_regs *regs) { u64 start_clock; u64 finish_clock; + u64 clock; int ret; /* @@ -1492,8 +1505,10 @@ perf_event_nmi_handler(unsigned int cmd, struct pt_regs *regs) start_clock = sched_clock(); ret = x86_pmu.handle_irq(regs); finish_clock = sched_clock(); + clock = finish_clock - start_clock; - perf_sample_event_took(finish_clock - start_clock); + perf_calculate_nmi_overhead(clock); + perf_sample_event_took(clock); return ret; } diff --git a/arch/x86/events/perf_event.h b/arch/x86/events/perf_event.h index a77ee02..7a03384 100644 --- a/arch/x86/events/perf_event.h +++ b/arch/x86/events/perf_event.h @@ -230,6 +230,8 @@ struct cpu_hw_events { struct intel_excl_cntrs *excl_cntrs; int excl_thread_id; /* 0 or 1 */ + struct perf_overhead_entry nmi_overhead; + /* * AMD specific bits */ diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h index bb0ecf0..fe7b1fb 100644 --- a/include/uapi/linux/perf_event.h +++ b/include/uapi/linux/perf_event.h @@ -1001,6 +1001,7 @@ enum perf_record_overhead_type { PERF_CORE_OVERHEAD = 0, PERF_PMU_OVERHEAD = 20, + PERF_PMU_SAMPLE_OVERHEAD = 20, PERF_OVERHEAD_MAX, }; -- 2.5.5