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 D96D6C43381 for ; Mon, 18 Feb 2019 14:55:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B3D6E21479 for ; Mon, 18 Feb 2019 14:55:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730211AbfBROzQ (ORCPT ); Mon, 18 Feb 2019 09:55:16 -0500 Received: from mail-wr1-f66.google.com ([209.85.221.66]:36397 "EHLO mail-wr1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730321AbfBROzQ (ORCPT ); Mon, 18 Feb 2019 09:55:16 -0500 Received: by mail-wr1-f66.google.com with SMTP id o17so18716469wrw.3 for ; Mon, 18 Feb 2019 06:55:14 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=u2EwF0qQ8fIwZ8XAhIn8rabEJP9DpcagTnKdKR/HstQ=; b=niNAeqaXIRC5aJ6w1nQLzdqGAaMNv6m2C8ERsBwASaKYgxeH94cPkhIOQ1IKNUfvbm upPwLHngn/+IqaEtKIrbrexF201oZ/ZidavF+fBFRpUowFc0t7ez2G/T7n8pzN+vk7GZ 1KiD+c9fBjbMndf0zqusB7171L9h8Sh7QnDYW/nWrYY6F55CyE4Nck03Ckge/rp46AjR rOlWT7vZ93VmCwgF1xgevS/Y15Sa1UWG7ekfmXXYuqInTIvIVwLyIIkM/HZtAEu4Jakq MxrTRKbCJg29Opkno49WC1+SIqRLN3YvYSGcThJAjzcZDU7wpsWX4FoW2pEBv05ezRjS tLYA== X-Gm-Message-State: AHQUAubOdF5uAql8BiLJHYSCHBi6VNmzaguB4IaH4w6ymHrpbHRR0pNo E0bOik9pGy+KVqzg5PHos446z3M= X-Google-Smtp-Source: AHgI3IbPA9LFkkUzjGdZnWqZJsxtlPzXDBEh1E69+NuAUKSJUjgLFFO+ouh9KGO7L/4atKxXzwWMZg== X-Received: by 2002:adf:f103:: with SMTP id r3mr18553754wro.50.1550501713782; Mon, 18 Feb 2019 06:55:13 -0800 (PST) Received: from localhost.localdomain ([146.247.46.6]) by smtp.gmail.com with ESMTPSA id n11sm10172528wrw.60.2019.02.18.06.55.12 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 18 Feb 2019 06:55:13 -0800 (PST) From: Slavomir Kaslev To: rostedt@vmware.com, rostedt@goodmis.org Cc: linux-trace-devel@vger.kernel.org, slavomir.kaslev@gmail.com Subject: [RFC PATCH v7 12/13] trace-cmd: Add splice() recording from FIFO without additional pipe buffer Date: Mon, 18 Feb 2019 16:54:48 +0200 Message-Id: <20190218145449.13360-13-kaslevs@vmware.com> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20190218145449.13360-1-kaslevs@vmware.com> References: <20190218145449.13360-1-kaslevs@vmware.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-trace-devel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-trace-devel@vger.kernel.org When `trace-cmd record` is reading tracing data over FIFO we can do a direct splice from the FIFO to the output file descriptor instead of doing two through an additional pipe buffer. This patch implements specialized tracecmd_recorder data transfer version for this case. Signed-off-by: Slavomir Kaslev --- include/trace-cmd/trace-cmd.h | 3 +- lib/trace-cmd/trace-recorder.c | 70 ++++++++++++++++++++++++++++------ 2 files changed, 61 insertions(+), 12 deletions(-) diff --git a/include/trace-cmd/trace-cmd.h b/include/trace-cmd/trace-cmd.h index 6a21e66..52962e9 100644 --- a/include/trace-cmd/trace-cmd.h +++ b/include/trace-cmd/trace-cmd.h @@ -270,8 +270,9 @@ struct tracecmd_output *tracecmd_get_output_handle_fd(int fd); enum { TRACECMD_RECORD_NOSPLICE = (1 << 0), /* Use read instead of splice */ - TRACECMD_RECORD_SNAPSHOT = (1 << 1), /* extract from snapshot */ + TRACECMD_RECORD_SNAPSHOT = (1 << 1), /* Extract from snapshot */ TRACECMD_RECORD_BLOCK = (1 << 2), /* Block on splice write */ + TRACECMD_RECORD_NOBRASS = (1 << 3), /* Splice directly without a brass pipe */ }; void tracecmd_free_recorder(struct tracecmd_recorder *recorder); diff --git a/lib/trace-cmd/trace-recorder.c b/lib/trace-cmd/trace-recorder.c index d66f112..8058d71 100644 --- a/lib/trace-cmd/trace-recorder.c +++ b/lib/trace-cmd/trace-recorder.c @@ -8,6 +8,7 @@ #include #include #include +#include #include #include @@ -26,6 +27,8 @@ # define SPLICE_F_GIFT 8 #endif +#define POLL_TIMEOUT_MS 1000 + struct tracecmd_recorder { int fd; int fd1; @@ -40,6 +43,7 @@ struct tracecmd_recorder { int pages; int count; unsigned fd_flags; + unsigned trace_fd_flags; unsigned flags; }; @@ -127,6 +131,8 @@ tracecmd_create_buffer_recorder_fd2(int fd, int fd2, int cpu, unsigned flags, if (!(recorder->flags & TRACECMD_RECORD_BLOCK)) recorder->fd_flags |= SPLICE_F_NONBLOCK; + recorder->trace_fd_flags = SPLICE_F_MOVE; + /* Init to know what to free and release */ recorder->trace_fd = -1; recorder->brass[0] = -1; @@ -171,7 +177,8 @@ tracecmd_create_buffer_recorder_fd2(int fd, int fd2, int cpu, unsigned flags, goto out_free; } - if ((recorder->flags & TRACECMD_RECORD_NOSPLICE) == 0) { + if (!(recorder->flags & (TRACECMD_RECORD_NOSPLICE | + TRACECMD_RECORD_NOBRASS))) { ret = pipe(recorder->brass); if (ret < 0) goto out_free; @@ -372,7 +379,7 @@ static long splice_data(struct tracecmd_recorder *recorder) long ret; read = splice(recorder->trace_fd, NULL, recorder->brass[1], NULL, - recorder->pipe_size, SPLICE_F_MOVE); + recorder->pipe_size, recorder->trace_fd_flags); if (read < 0) { if (errno != EAGAIN && errno != EINTR) { warning("recorder error in splice input"); @@ -399,6 +406,39 @@ static long splice_data(struct tracecmd_recorder *recorder) return total_read; } +/* + * Returns -1 on error. + * or bytes of data read. + */ +static long direct_splice_data(struct tracecmd_recorder *recorder) +{ + struct pollfd pfd = { + .fd = recorder->trace_fd, + .events = POLLIN, + }; + long read; + int ret; + + ret = poll(&pfd, 1, POLL_TIMEOUT_MS); + if (ret < 0) + return -1; + + if (!(pfd.revents | POLLIN)) + return 0; + + read = splice(recorder->trace_fd, NULL, recorder->fd, NULL, + recorder->pipe_size, recorder->trace_fd_flags); + if (read < 0) { + if (errno == EAGAIN || errno == EINTR) + return 0; + + warning("recorder error in splice input"); + return -1; + } + + return read; +} + /* * Returns -1 on error. * or bytes of data read. @@ -433,6 +473,17 @@ static long read_data(struct tracecmd_recorder *recorder) return r; } +static long move_data(struct tracecmd_recorder *recorder) +{ + if (recorder->flags & TRACECMD_RECORD_NOSPLICE) + return read_data(recorder); + + if (recorder->flags & TRACECMD_RECORD_NOBRASS) + return direct_splice_data(recorder); + + return splice_data(recorder); +} + static void set_nonblock(struct tracecmd_recorder *recorder) { long flags; @@ -440,8 +491,11 @@ static void set_nonblock(struct tracecmd_recorder *recorder) /* Do not block on reads for flushing */ flags = fcntl(recorder->trace_fd, F_GETFL); fcntl(recorder->trace_fd, F_SETFL, flags | O_NONBLOCK); + recorder->trace_fd_flags |= SPLICE_F_NONBLOCK; - /* Do not block on streams for write */ + /* Do not block on pipes for write */ + flags = fcntl(recorder->fd, F_GETFL); + fcntl(recorder->fd, F_SETFL, flags | O_NONBLOCK); recorder->fd_flags |= SPLICE_F_NONBLOCK; } @@ -455,10 +509,7 @@ long tracecmd_flush_recording(struct tracecmd_recorder *recorder) set_nonblock(recorder); do { - if (recorder->flags & TRACECMD_RECORD_NOSPLICE) - ret = read_data(recorder); - else - ret = splice_data(recorder); + ret = move_data(recorder); if (ret < 0) return ret; total += ret; @@ -503,10 +554,7 @@ int tracecmd_start_recording(struct tracecmd_recorder *recorder, unsigned long s read = 0; do { - if (recorder->flags & TRACECMD_RECORD_NOSPLICE) - ret = read_data(recorder); - else - ret = splice_data(recorder); + ret = move_data(recorder); if (ret < 0) return ret; read += ret; -- 2.19.1