From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A8036C43381 for ; Thu, 14 Feb 2019 09:43:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 83DF7222D2 for ; Thu, 14 Feb 2019 09:43:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2437979AbfBNJnL (ORCPT ); Thu, 14 Feb 2019 04:43:11 -0500 Received: from mga09.intel.com ([134.134.136.24]:32216 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2395247AbfBNJnC (ORCPT ); Thu, 14 Feb 2019 04:43:02 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by orsmga102.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 14 Feb 2019 01:43:01 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.58,368,1544515200"; d="scan'208";a="124411778" Received: from devel-ww.sh.intel.com ([10.239.48.128]) by fmsmga008.fm.intel.com with ESMTP; 14 Feb 2019 01:42:59 -0800 From: Wei Wang To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, pbonzini@redhat.com, ak@linux.intel.com, peterz@infradead.org Cc: kan.liang@intel.com, mingo@redhat.com, rkrcmar@redhat.com, like.xu@intel.com, wei.w.wang@intel.com, jannh@google.com, arei.gonglei@huawei.com, jmattson@google.com Subject: [PATCH v5 07/12] perf/x86: no counter allocation support Date: Thu, 14 Feb 2019 17:06:09 +0800 Message-Id: <1550135174-5423-8-git-send-email-wei.w.wang@intel.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1550135174-5423-1-git-send-email-wei.w.wang@intel.com> References: <1550135174-5423-1-git-send-email-wei.w.wang@intel.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In some cases, an event may be created without needing a counter allocation. For example, an lbr event may be created by the host only to help save/restore the lbr stack on the vCPU context switching. This patch adds a "no_counter" attr boolean to let the callers explicitly tell the perf core that no counter is needed. Signed-off-by: Wei Wang --- arch/x86/events/core.c | 12 ++++++++++++ include/linux/perf_event.h | 5 +++++ include/uapi/linux/perf_event.h | 3 ++- 3 files changed, 19 insertions(+), 1 deletion(-) diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c index 374a197..c09f03b 100644 --- a/arch/x86/events/core.c +++ b/arch/x86/events/core.c @@ -410,6 +410,9 @@ int x86_setup_perfctr(struct perf_event *event) struct hw_perf_event *hwc = &event->hw; u64 config; + if (is_no_counter_event(event)) + return 0; + if (!is_sampling_event(event)) { hwc->sample_period = x86_pmu.max_period; hwc->last_period = hwc->sample_period; @@ -1209,6 +1212,12 @@ static int x86_pmu_add(struct perf_event *event, int flags) hwc = &event->hw; n0 = cpuc->n_events; + + if (is_no_counter_event(event)) { + n = n0; + goto done_collect; + } + ret = n = collect_events(cpuc, event, false); if (ret < 0) goto out; @@ -1387,6 +1396,9 @@ static void x86_pmu_del(struct perf_event *event, int flags) if (cpuc->txn_flags & PERF_PMU_TXN_ADD) goto do_del; + if (is_no_counter_event(event)) + goto do_del; + /* * Not a TXN, therefore cleanup properly. */ diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index 1d5c551..3993e66 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -1009,6 +1009,11 @@ static inline bool is_sampling_event(struct perf_event *event) return event->attr.sample_period != 0; } +static inline bool is_no_counter_event(struct perf_event *event) +{ + return event->attr.no_counter; +} + /* * Return 1 for a software event, 0 for a hardware event */ diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h index 9de8780..ec97a70 100644 --- a/include/uapi/linux/perf_event.h +++ b/include/uapi/linux/perf_event.h @@ -372,7 +372,8 @@ struct perf_event_attr { context_switch : 1, /* context switch data */ write_backward : 1, /* Write ring buffer from end to beginning */ namespaces : 1, /* include namespaces data */ - __reserved_1 : 35; + no_counter : 1, /* no counter allocation */ + __reserved_1 : 34; union { __u32 wakeup_events; /* wakeup every n events */ -- 2.7.4