From patchwork Wed Dec 6 14:41:14 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Arnaldo Carvalho de Melo X-Patchwork-Id: 120857 Delivered-To: patch@linaro.org Received: by 10.140.22.227 with SMTP id 90csp7141136qgn; Wed, 6 Dec 2017 06:44:04 -0800 (PST) X-Google-Smtp-Source: AGs4zMb53bC+r6Nrd0fsIWa56a7c7DpugK5W+gM341Cw65R9ew7QiXK42SFOuVcyoVkA32vOQTGk X-Received: by 10.98.12.211 with SMTP id 80mr3024031pfm.169.1512571444864; Wed, 06 Dec 2017 06:44:04 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1512571444; cv=none; d=google.com; s=arc-20160816; b=kl0w921XDJvw+7GpEz5BLvzW4Cwt+Zr1Ou4u+WZsHFxM0IzLs+5UOXIt6SouU4Wx+5 AdYxWWvf7nFhz/7gbSnU0OpbPuF/pOUJJxiWSmHCEEVcH9GCSlZIZUpMVDbJIXpnb4rF 4xVJbBnxdlXAZrqwPDuDREZX+XyKpzl0m9EHOj0LxOchRUK5oCmMsa46ZWCSL6NxNxoF rGrEwNAjUeGcet822FCcAfmMWYIHy7BifLUr3D0eU2RLFLfN7NlUbFW90Kb1qaaYsAW4 6CXNwEuu0xICSKtt0cFiE3azTXAg/PnZ4NyOocEwVw0IQH/oFp2vV+PisOBZwqts//Xo S9nA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:references:in-reply-to:message-id:date :subject:cc:to:from:dmarc-filter:arc-authentication-results; bh=P+eMluM0OBsSU/FOxhc70Tkoqh0NX3htQvbX10T245U=; b=PHlKByHDsLU6IXAIDCuHx/ZVMhvBL8iYcnZl7UALRIyJj9Re4DEQVJibD+F/apUKZM rAnfEybH5Pog5Grmd23/8SVlmymQMrON7NEzyamzMh63EF7ZLkr/Nb0kiRlZGYvbBTvb 5JwXmrQQy8/mBby5bgKJN1lpM2GeplWm0HC8suw4c/ZiMOlzjlmTWQ5dE1Nthjodvy9f rF5dSIZ7lgb4UBYvJaju6C+aHzNJLqZSDsF0Mhsu3SwEgIyxIBq4lvZB+CALz1h1faIy zwV6uiif0WQd+XR55hTjrAEBjTqzwj0lbk6VJe2EJB8I0E7CGV9Hlfv0tzgsnsL+DQYo efww== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id a73si1988201pge.281.2017.12.06.06.44.04; Wed, 06 Dec 2017 06:44:04 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753055AbdLFOoC (ORCPT + 28 others); Wed, 6 Dec 2017 09:44:02 -0500 Received: from mail.kernel.org ([198.145.29.99]:58682 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752997AbdLFOnu (ORCPT ); Wed, 6 Dec 2017 09:43:50 -0500 Received: from jouet.infradead.org (unknown [179.97.41.186]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 1BC76218B0; Wed, 6 Dec 2017 14:43:46 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1BC76218B0 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=acme@kernel.org From: Arnaldo Carvalho de Melo To: Ingo Molnar Cc: linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, Wang Nan , Jiri Olsa , Mengting Zhang , Arnaldo Carvalho de Melo Subject: [PATCH 35/36] perf mmap: Don't discard prev in backward mode Date: Wed, 6 Dec 2017 11:41:14 -0300 Message-Id: <20171206144115.15097-36-acme@kernel.org> X-Mailer: git-send-email 2.13.6 In-Reply-To: <20171206144115.15097-1-acme@kernel.org> References: <20171206144115.15097-1-acme@kernel.org> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Wang Nan 'perf record' can switch its output data file. The new output should only store the data after switching. However, in overwrite backward mode, the new output still can have data from before switching. That also brings extra overhead. At the end of mmap_read(), the position of the processed ring buffer is saved in md->prev. Next mmap_read should be end in md->prev if it is not overwriten. That avoids processing duplicate data. However, md->prev is discarded. So next the mmap_read() has to process whole valid ring buffer, which probably includes old processed data. Avoid calling backward_rb_find_range() when md->prev is still available. Signed-off-by: Wang Nan Tested-by: Kan Liang Acked-by: Namhyung Kim Cc: Jiri Olsa Cc: Mengting Zhang Link: http://lkml.kernel.org/r/20171204165107.95327-3-wangnan0@huawei.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/mmap.c | 33 +++++++++++++++------------------ 1 file changed, 15 insertions(+), 18 deletions(-) -- 2.13.6 diff --git a/tools/perf/util/mmap.c b/tools/perf/util/mmap.c index 3f262e707a41..5f8cb1583e53 100644 --- a/tools/perf/util/mmap.c +++ b/tools/perf/util/mmap.c @@ -267,18 +267,6 @@ static int backward_rb_find_range(void *buf, int mask, u64 head, u64 *start, u64 return -1; } -static int rb_find_range(void *data, int mask, u64 head, u64 old, - u64 *start, u64 *end, bool backward) -{ - if (!backward) { - *start = old; - *end = head; - return 0; - } - - return backward_rb_find_range(data, mask, head, start, end); -} - int perf_mmap__push(struct perf_mmap *md, bool backward, void *to, int push(void *to, void *buf, size_t size)) { @@ -290,19 +278,28 @@ int perf_mmap__push(struct perf_mmap *md, bool backward, void *buf; int rc = 0; - if (rb_find_range(data, md->mask, head, old, &start, &end, backward)) - return -1; + start = backward ? head : old; + end = backward ? old : head; if (start == end) return 0; size = end - start; if (size > (unsigned long)(md->mask) + 1) { - WARN_ONCE(1, "failed to keep up with mmap data. (warn only once)\n"); + if (!backward) { + WARN_ONCE(1, "failed to keep up with mmap data. (warn only once)\n"); - md->prev = head; - perf_mmap__consume(md, backward); - return 0; + md->prev = head; + perf_mmap__consume(md, backward); + return 0; + } + + /* + * Backward ring buffer is full. We still have a chance to read + * most of data from it. + */ + if (backward_rb_find_range(data, md->mask, head, &start, &end)) + return -1; } if ((start & md->mask) + size != (end & md->mask)) {