Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756021AbcLBVWK (ORCPT ); Fri, 2 Dec 2016 16:22:10 -0500 Received: from mga05.intel.com ([192.55.52.43]:20536 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751972AbcLBVUn (ORCPT ); Fri, 2 Dec 2016 16:20:43 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.33,288,1477983600"; d="scan'208";a="1093847509" 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 05/13] perf/core: output side-band events overhead Date: Fri, 2 Dec 2016 16:19:13 -0500 Message-Id: <1480713561-6617-6-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: 3052 Lines: 109 From: Kan Liang Iterating all events which need to receive side-band events also bring some overhead. The side-band events overhead PERF_CORE_SB_OVERHEAD is a common overhead type. Signed-off-by: Kan Liang --- include/linux/perf_event.h | 2 ++ include/uapi/linux/perf_event.h | 1 + kernel/events/core.c | 27 ++++++++++++++++++++++++--- 3 files changed, 27 insertions(+), 3 deletions(-) diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index 351d321..fe4ca0b 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -765,6 +765,8 @@ struct perf_event_context { #endif void *task_ctx_data; /* pmu specific data */ struct rcu_head rcu_head; + + struct perf_overhead_entry sb_overhead; }; /* diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h index 355086f..bdf2eec 100644 --- a/include/uapi/linux/perf_event.h +++ b/include/uapi/linux/perf_event.h @@ -1000,6 +1000,7 @@ struct perf_branch_entry { enum perf_record_overhead_type { PERF_CORE_OVERHEAD = 0, PERF_CORE_MUX_OVERHEAD = 0, + PERF_CORE_SB_OVERHEAD, PERF_PMU_OVERHEAD = 20, PERF_PMU_SAMPLE_OVERHEAD = 20, diff --git a/kernel/events/core.c b/kernel/events/core.c index 025a19d..85706fb 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -1830,8 +1830,12 @@ event_sched_out(struct perf_event *event, if (event->attr.exclusive || !cpuctx->active_oncpu) cpuctx->exclusive = 0; - if (log_overhead && cpuctx->mux_overhead.nr) - perf_log_overhead(event, PERF_CORE_MUX_OVERHEAD, &cpuctx->mux_overhead); + if (log_overhead) { + if (cpuctx->mux_overhead.nr) + perf_log_overhead(event, PERF_CORE_MUX_OVERHEAD, &cpuctx->mux_overhead); + if (ctx->sb_overhead.nr) + perf_log_overhead(event, PERF_CORE_SB_OVERHEAD, &ctx->sb_overhead); + } perf_pmu_enable(event->pmu); } @@ -6131,6 +6135,13 @@ static void perf_iterate_sb_cpu(perf_iterate_f output, void *data) } } +static void +perf_calculate_sb_overhead(struct perf_event_context *ctx, u64 time) +{ + ctx->sb_overhead.nr++; + ctx->sb_overhead.time += time; +} + /* * Iterate all events that need to receive side-band events. * @@ -6141,9 +6152,12 @@ static void perf_iterate_sb(perf_iterate_f output, void *data, struct perf_event_context *task_ctx) { + struct perf_event_context *overhead_ctx = task_ctx; struct perf_event_context *ctx; + u64 start_clock, end_clock; int ctxn; + start_clock = perf_clock(); rcu_read_lock(); preempt_disable(); @@ -6161,12 +6175,19 @@ perf_iterate_sb(perf_iterate_f output, void *data, for_each_task_context_nr(ctxn) { ctx = rcu_dereference(current->perf_event_ctxp[ctxn]); - if (ctx) + if (ctx) { perf_iterate_ctx(ctx, output, data, false); + if (!overhead_ctx) + overhead_ctx = ctx; + } } done: preempt_enable(); rcu_read_unlock(); + + end_clock = perf_clock(); + if (overhead_ctx) + perf_calculate_sb_overhead(overhead_ctx, end_clock - start_clock); } /* -- 2.5.5