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=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,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 C723ACA9EA0 for ; Tue, 22 Oct 2019 09:58:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A76F020B7C for ; Tue, 22 Oct 2019 09:58:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731652AbfJVJ6s (ORCPT ); Tue, 22 Oct 2019 05:58:48 -0400 Received: from mga12.intel.com ([192.55.52.136]:26087 "EHLO mga12.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731220AbfJVJ6q (ORCPT ); Tue, 22 Oct 2019 05:58:46 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga007.fm.intel.com ([10.253.24.52]) by fmsmga106.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 22 Oct 2019 02:58:46 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.67,326,1566889200"; d="scan'208";a="197074473" Received: from black.fi.intel.com (HELO black.fi.intel.com.) ([10.237.72.28]) by fmsmga007.fm.intel.com with ESMTP; 22 Oct 2019 02:58:43 -0700 From: Alexander Shishkin To: Peter Zijlstra Cc: Arnaldo Carvalho de Melo , Ingo Molnar , linux-kernel@vger.kernel.org, jolsa@redhat.com, adrian.hunter@intel.com, mathieu.poirier@linaro.org, mark.rutland@arm.com, Alexander Shishkin Subject: [PATCH v2 3/4] perf/x86/intel/pt: Add sampling support Date: Tue, 22 Oct 2019 12:58:11 +0300 Message-Id: <20191022095812.67071-4-alexander.shishkin@linux.intel.com> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20191022095812.67071-1-alexander.shishkin@linux.intel.com> References: <20191022095812.67071-1-alexander.shishkin@linux.intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Add AUX sampling support to the PT PMU: implement an NMI-safe callback that takes a snapshot of the buffer without touching the event states. This is done for PT events that don't use PMIs, that is, snapshot mode (RO mapping of the AUX area). Signed-off-by: Alexander Shishkin --- arch/x86/events/intel/pt.c | 54 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 54 insertions(+) diff --git a/arch/x86/events/intel/pt.c b/arch/x86/events/intel/pt.c index 170f3b402274..2f20d5a333c1 100644 --- a/arch/x86/events/intel/pt.c +++ b/arch/x86/events/intel/pt.c @@ -1208,6 +1208,13 @@ pt_buffer_setup_aux(struct perf_event *event, void **pages, if (!nr_pages) return NULL; + /* + * Only support AUX sampling in snapshot mode, where we don't + * generate NMIs. + */ + if (event->attr.aux_sample_size && !snapshot) + return NULL; + if (cpu == -1) cpu = raw_smp_processor_id(); node = cpu_to_node(cpu); @@ -1506,6 +1513,52 @@ static void pt_event_stop(struct perf_event *event, int mode) } } +static long pt_event_snapshot_aux(struct perf_event *event, + struct perf_output_handle *handle, + unsigned long size) +{ + struct pt *pt = this_cpu_ptr(&pt_ctx); + struct pt_buffer *buf = perf_get_aux(&pt->handle); + unsigned long from = 0, to; + long ret; + + if (WARN_ON_ONCE(!buf)) + return 0; + + /* + * Sampling is only allowed on snapshot events; + * see pt_buffer_setup_aux(). + */ + if (WARN_ON_ONCE(!buf->snapshot)) + return 0; + + /* + * Here, handle_nmi tells us if the tracing is on + */ + if (READ_ONCE(pt->handle_nmi)) + pt_config_stop(event); + + pt_read_offset(buf); + pt_update_head(pt); + + to = local_read(&buf->data_size); + if (to < size) + from = buf->nr_pages << PAGE_SHIFT; + from += to - size; + + ret = perf_output_copy_aux(&pt->handle, handle, from, to); + + /* + * If the tracing was on when we turned up, restart it. + * Compiler barrier not needed as we couldn't have been + * preempted by anything that touches pt->handle_nmi. + */ + if (pt->handle_nmi) + pt_config_start(event); + + return ret; +} + static void pt_event_del(struct perf_event *event, int mode) { pt_event_stop(event, PERF_EF_UPDATE); @@ -1625,6 +1678,7 @@ static __init int pt_init(void) pt_pmu.pmu.del = pt_event_del; pt_pmu.pmu.start = pt_event_start; pt_pmu.pmu.stop = pt_event_stop; + pt_pmu.pmu.snapshot_aux = pt_event_snapshot_aux; pt_pmu.pmu.read = pt_event_read; pt_pmu.pmu.setup_aux = pt_buffer_setup_aux; pt_pmu.pmu.free_aux = pt_buffer_free_aux; -- 2.23.0