Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932843AbcLHV2z (ORCPT ); Thu, 8 Dec 2016 16:28:55 -0500 Received: from mga06.intel.com ([134.134.136.31]:29684 "EHLO mga06.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932279AbcLHV20 (ORCPT ); Thu, 8 Dec 2016 16:28:26 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.33,321,1477983600"; d="scan'208";a="40528645" 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 V3 4/6] perf/core: calculate multiplexing overhead Date: Thu, 8 Dec 2016 16:27:12 -0500 Message-Id: <1481232434-3574-5-git-send-email-kan.liang@intel.com> X-Mailer: git-send-email 2.4.3 In-Reply-To: <1481232434-3574-1-git-send-email-kan.liang@intel.com> References: <1481232434-3574-1-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: 1847 Lines: 62 From: Kan Liang Multiplexing overhead is one of the key overhead when the number of events is more than available counters. The multiplexing overhead PERF_CORE_MUX_OVERHEAD is a common overhead type. Signed-off-by: Kan Liang --- include/uapi/linux/perf_event.h | 1 + kernel/events/core.c | 9 +++++++++ 2 files changed, 10 insertions(+) diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h index 23b7963..c488336 100644 --- a/include/uapi/linux/perf_event.h +++ b/include/uapi/linux/perf_event.h @@ -1001,6 +1001,7 @@ struct perf_branch_entry { */ enum perf_record_overhead_type { /* common overhead */ + PERF_CORE_MUX_OVERHEAD = 0, /* PMU specific */ PERF_OVERHEAD_MAX, }; diff --git a/kernel/events/core.c b/kernel/events/core.c index dbde193..28468ae 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -3326,6 +3326,7 @@ static void rotate_ctx(struct perf_event_context *ctx) static int perf_rotate_context(struct perf_cpu_context *cpuctx) { struct perf_event_context *ctx = NULL; + u64 start_clock, end_clock; int rotate = 0; if (cpuctx->ctx.nr_events) { @@ -3342,6 +3343,7 @@ static int perf_rotate_context(struct perf_cpu_context *cpuctx) if (!rotate) goto done; + start_clock = perf_clock(); perf_ctx_lock(cpuctx, cpuctx->task_ctx); perf_pmu_disable(cpuctx->ctx.pmu); @@ -3357,6 +3359,13 @@ static int perf_rotate_context(struct perf_cpu_context *cpuctx) perf_pmu_enable(cpuctx->ctx.pmu); perf_ctx_unlock(cpuctx, cpuctx->task_ctx); + + /* calculate multiplexing overhead */ + if (cpuctx->ctx.pmu->stat) { + end_clock = perf_clock(); + cpuctx->overhead[PERF_CORE_MUX_OVERHEAD].nr++; + cpuctx->overhead[PERF_CORE_MUX_OVERHEAD].time += end_clock - start_clock; + } done: return rotate; -- 2.4.3