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=-12.0 required=3.0 tests=INCLUDES_PATCH, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED 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 997FAC43441 for ; Mon, 19 Nov 2018 12:20:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6B9EF2086A for ; Mon, 19 Nov 2018 12:20:40 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6B9EF2086A Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728933AbeKSWoG (ORCPT ); Mon, 19 Nov 2018 17:44:06 -0500 Received: from mx1.redhat.com ([209.132.183.28]:54894 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728679AbeKSWoG (ORCPT ); Mon, 19 Nov 2018 17:44:06 -0500 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 957DF820E3; Mon, 19 Nov 2018 12:20:38 +0000 (UTC) Received: from krava.redhat.com (ovpn-204-39.brq.redhat.com [10.40.204.39]) by smtp.corp.redhat.com (Postfix) with ESMTP id AE0B55C8A1; Mon, 19 Nov 2018 12:20:36 +0000 (UTC) From: Jiri Olsa To: Arnaldo Carvalho de Melo Cc: lkml , Ingo Molnar , Namhyung Kim , Alexander Shishkin , Peter Zijlstra , David Miller Subject: [PATCH 07/12] perf top: Use cond variable instead of the lock Date: Mon, 19 Nov 2018 13:20:11 +0100 Message-Id: <20181119122016.22423-8-jolsa@kernel.org> In-Reply-To: <20181119122016.22423-1-jolsa@kernel.org> References: <20181119122016.22423-1-jolsa@kernel.org> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.26]); Mon, 19 Nov 2018 12:20:38 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Using conditional variable logic to synchronize between reading and processing threads. Currently it's done by having mutex around rotation code. Using posix cond variable to sync both threads after queues rotation: process thread: - detects data - switches queues - set rotate variable - waits in pthread_cond_wait read thread: - detects rotate is set - kicks process thread with pthread_cond_signal After this rotation is safely completed and both threads can continue with the new queue. Link: http://lkml.kernel.org/n/tip-3rdeg23rv3brvy1pwt3igvyw@git.kernel.org Signed-off-by: Jiri Olsa --- tools/perf/builtin-top.c | 24 +++++++++++++++++------- tools/perf/util/top.h | 4 +++- 2 files changed, 20 insertions(+), 8 deletions(-) diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c index f8dcdf0f54e1..ca2a1557ac07 100644 --- a/tools/perf/builtin-top.c +++ b/tools/perf/builtin-top.c @@ -846,13 +846,18 @@ static void perf_top__mmap_read_idx(struct perf_top *top, int idx) if (ret && ret != -1) break; - pthread_mutex_lock(&top->qe.lock); ret = ordered_events__queue(top->qe.in, event, timestamp, 0); - pthread_mutex_unlock(&top->qe.lock); - - perf_mmap__consume(md); if (ret) break; + + perf_mmap__consume(md); + + if (top->qe.rotate) { + pthread_mutex_lock(&top->qe.mutex); + top->qe.rotate = false; + pthread_cond_signal(&top->qe.cond); + pthread_mutex_unlock(&top->qe.mutex); + } } perf_mmap__read_done(md); @@ -1059,9 +1064,12 @@ static void *process_thread(void *arg) continue; } - pthread_mutex_lock(&top->qe.lock); out = rotate_queues(top); - pthread_mutex_unlock(&top->qe.lock); + + pthread_mutex_lock(&top->qe.mutex); + top->qe.rotate = true; + pthread_cond_wait(&top->qe.cond, &top->qe.mutex); + pthread_mutex_unlock(&top->qe.mutex); if (ordered_events__flush(out, OE_FLUSH__TOP)) pr_err("failed to process events\n"); @@ -1151,7 +1159,8 @@ static void init_process_thread(struct perf_top *top) ordered_events__set_copy_on_queue(&top->qe.data[0], true); ordered_events__set_copy_on_queue(&top->qe.data[1], true); top->qe.in = &top->qe.data[0]; - pthread_mutex_init(&top->qe.lock, NULL); + pthread_mutex_init(&top->qe.mutex, NULL); + pthread_cond_init(&top->qe.cond, NULL); } static int __cmd_top(struct perf_top *top) @@ -1272,6 +1281,7 @@ static int __cmd_top(struct perf_top *top) out_join: pthread_join(thread, NULL); out_join_thread: + pthread_cond_signal(&top->qe.cond); pthread_join(thread_process, NULL); out_delete: perf_session__delete(top->session); diff --git a/tools/perf/util/top.h b/tools/perf/util/top.h index 5f503293cfd8..5bce62ebcf14 100644 --- a/tools/perf/util/top.h +++ b/tools/perf/util/top.h @@ -44,7 +44,9 @@ struct perf_top { struct { struct ordered_events *in; struct ordered_events data[2]; - pthread_mutex_t lock; + bool rotate; + pthread_mutex_t mutex; + pthread_cond_t cond; } qe; }; -- 2.17.2