From patchwork Mon Dec 2 10:17:25 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Masami Hiramatsu (Google)" X-Patchwork-Id: 11268941 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 692F8109A for ; Mon, 2 Dec 2019 10:17:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3E0B1217F5 for ; Mon, 2 Dec 2019 10:17:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1575281856; bh=CQwLaPfjyq5qvrJ95mM35q4XZZrZIKEuQkYcOzmmww4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=uWYSx5qyC7vI+8tSdlI6h+1Rv1/sm0Lc929v200WOPbq5zbgnvPXQgv2L/YYgVqd8 hPfIAo1/42EEpHCoFCfxuoIHlX3kMQ2pmcZgDeja+FvMsLOrD4sVMjxBIH2N238jKd 0qW7CFAoO+4LVwl5DE7GOGFewdnJzocfbDzrqD14= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727498AbfLBKRc (ORCPT ); Mon, 2 Dec 2019 05:17:32 -0500 Received: from mail.kernel.org ([198.145.29.99]:33678 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727364AbfLBKRc (ORCPT ); Mon, 2 Dec 2019 05:17:32 -0500 Received: from localhost.localdomain (NE2965lan1.rev.em-net.ne.jp [210.141.244.193]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 5B12F217D9; Mon, 2 Dec 2019 10:17:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1575281850; bh=CQwLaPfjyq5qvrJ95mM35q4XZZrZIKEuQkYcOzmmww4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ofKz3D+UYOSrcblzVDZ44gBbY0L3/A79zqd3D02vsq1wQHg4F91Mv2avrpk2hbH1s ocfS8pfqx2g6I359u4PcAzv0breZDSdn0WfYTJe8FY3X6Rsw7wIt6ZlZx0FPgU0eKX zByI/xtCEyIsfeahVWhemL8DuCvA12MlXW0/HH0Y= From: Masami Hiramatsu To: Steven Rostedt , Frank Rowand Cc: Ingo Molnar , Namhyung Kim , Tim Bird , Jiri Olsa , Arnaldo Carvalho de Melo , Tom Zanussi , Rob Herring , Andrew Morton , Thomas Gleixner , Greg Kroah-Hartman , Alexey Dobriyan , Jonathan Corbet , Linus Torvalds , linux-doc@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [RFC PATCH v4 22/22] Documentation: tracing: Add boot-time tracing document Date: Mon, 2 Dec 2019 19:17:25 +0900 Message-Id: <157528184501.22451.12534762470752205454.stgit@devnote2> X-Mailer: git-send-email 2.20.1 In-Reply-To: <157528159833.22451.14878731055438721716.stgit@devnote2> References: <157528159833.22451.14878731055438721716.stgit@devnote2> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Add a documentation about boot-time tracing options in boot config. Signed-off-by: Masami Hiramatsu --- Documentation/admin-guide/bootconfig.rst | 2 Documentation/trace/boottime-trace.rst | 184 ++++++++++++++++++++++++++++++ Documentation/trace/index.rst | 1 3 files changed, 187 insertions(+) create mode 100644 Documentation/trace/boottime-trace.rst diff --git a/Documentation/admin-guide/bootconfig.rst b/Documentation/admin-guide/bootconfig.rst index db35cee8a00a..ab015e512614 100644 --- a/Documentation/admin-guide/bootconfig.rst +++ b/Documentation/admin-guide/bootconfig.rst @@ -1,5 +1,7 @@ .. SPDX-License-Identifier: GPL-2.0 +.. _bootconfig: + ================== Boot Configuration ================== diff --git a/Documentation/trace/boottime-trace.rst b/Documentation/trace/boottime-trace.rst new file mode 100644 index 000000000000..1d10fdebf1b2 --- /dev/null +++ b/Documentation/trace/boottime-trace.rst @@ -0,0 +1,184 @@ +.. SPDX-License-Identifier: GPL-2.0 + +================= +Boot-time tracing +================= + +:Author: Masami Hiramatsu + +Overview +======== + +Boot-time tracing allows users to trace boot-time process including +device initialization with full features of ftrace including per-event +filter and actions, histograms, kprobe-events and synthetic-events, +and trace instances. +Since kernel cmdline is not enough to control these complex features, +this uses bootconfig file to describe tracing feature programming. + +Options in the Boot Config +========================== + +Here is the list of available options list for boot time tracing in +boot config file [1]_. All options are under "ftrace." or "kernel." +refix. See kernel parameters for the options which starts +with "kernel." prefix [2]_. + +.. [1] See :ref:`Documentation/admin-guide/bootconfig.rst ` +.. [2] See :ref:`Documentation/admin-guide/kernel-parameters.rst ` + +Ftrace Global Options +--------------------- + +Ftrace global options have "kernel." prefix in boot config, which means +these options are passed as a part of kernel legacy command line. + +kernel.tp_printk + Output trace-event data on printk buffer too. + +kernel.dump_on_oops [= MODE] + Dump ftrace on Oops. If MODE = 1 or omitted, dump trace buffer + on all CPUs. If MODE = 2, dump a buffer on a CPU which kicks Oops. + +kernel.traceoff_on_warning + Stop tracing if WARN_ON() occurs. + +kernel.fgraph_max_depth = MAX_DEPTH + Set MAX_DEPTH to maximum depth of fgraph tracer. + +kernel.fgraph_filters = FILTER[, FILTER2...] + Add fgraph tracing function filters. + +kernel.fgraph_notraces = FILTER[, FILTER2...] + Add fgraph non tracing function filters. + + +Ftrace Per-instance Options +--------------------------- + +These options can be used for each instance including global ftrace node. + +ftrace.[instance.INSTANCE.]options = OPT1[, OPT2[...]] + Enable given ftrace options. + +ftrace.[instance.INSTANCE.]trace_clock = CLOCK + Set given CLOCK to ftrace's trace_clock. + +ftrace.[instance.INSTANCE.]buffer_size = SIZE + Configure ftrace buffer size to SIZE. You can use "KB" or "MB" + for that SIZE. + +ftrace.[instance.INSTANCE.]alloc_snapshot + Allocate snapshot buffer. + +ftrace.[instance.INSTANCE.]cpumask = CPUMASK + Set CPUMASK as trace cpu-mask. + +ftrace.[instance.INSTANCE.]events = EVENT[, EVENT2[...]] + Enable given events on boot. You can use a wild card in EVENT. + +ftrace.[instance.INSTANCE.]tracer = TRACER + Set TRACER to current tracer on boot. (e.g. function) + +ftrace.[instance.INSTANCE.]ftrace.filters + This will take an array of tracing function filter rules + +ftrace.[instance.INSTANCE.]ftrace.notraces + This will take an array of NON-tracing function filter rules + + +Ftrace Per-Event Options +------------------------ + +These options are setting per-event options. + +ftrace.[instance.INSTANCE.]event.GROUP.EVENT.enable + Enables GROUP:EVENT tracing. + +ftrace.[instance.INSTANCE.]event.GROUP.EVENT.filter = FILTER + Set FILTER rule to the GROUP:EVENT. + +ftrace.[instance.INSTANCE.]event.GROUP.EVENT.actions = ACTION[, ACTION2[...]] + Set ACTIONs to the GROUP:EVENT. + +ftrace.[instance.INSTANCE.]event.kprobes.EVENT.probes = PROBE[, PROBE2[...]] + Defines new kprobe event based on PROBEs. It is able to define + multiple probes on one event, but those must have same type of + arguments. This option is available only for the event which + group name is "kprobes". + +ftrace.[instance.INSTANCE.]event.synthetic.EVENT.fields = FIELD[, FIELD2[...]] + Defines new synthetic event with FIELDs. Each field should be + "type varname". + +Note that kprobe and synthetic event definitions can be written under +instance node, but those are also visible from other instances. So please +take care for event name conflict. + + +Examples +======== + +For example, to add filter and actions for each event, define kprobe +events, and synthetic events with histogram, write a boot config like +below:: + + ftrace.event { + task.task_newtask { + filter = "pid < 128" + enable + } + kprobes.vfs_read { + probes = "vfs_read $arg1 $arg2" + filter = "common_pid < 200" + enable + } + synthetic.initcall_latency { + fields = "unsigned long func", "u64 lat" + actions = "hist:keys=func.sym,lat:vals=lat:sort=lat" + } + initcall.initcall_start { + actions = "hist:keys=func:ts0=common_timestamp.usecs" + } + initcall.initcall_finish { + actions = "hist:keys=func:lat=common_timestamp.usecs-$ts0:onmatch(initcall.initcall_start).initcall_latency(func,$lat)" + } + } + +Also, boottime tracing supports "instance" node, which allows us to run +several tracers for different purpose at once. For example, one tracer +is for tracing functions start with "user\_", and others tracing "kernel\_" +functions, you can write boot config as below:: + + ftrace.instance { + foo { + tracer = "function" + ftrace.filters = "user_*" + } + bar { + tracer = "function" + ftrace.filters = "kernel_*" + } + } + +The instance node also accepts event nodes so that each instance +can customize its event tracing. + +This boot-time tracing also supports ftrace kernel parameters via boot +config. +For example, following kernel parameters:: + + trace_options=sym-addr trace_event=initcall:* tp_printk trace_buf_size=1M ftrace=function ftrace_filter="vfs*" + +This can be written in boot config like below:: + + kernel { + trace_options = sym-addr + trace_event = "initcall:*" + tp_printk + trace_buf_size = 1M + ftrace = function + ftrace_filter = "vfs*" + } + +Note that parameters start with "kernel" prefix instead of "ftrace". diff --git a/Documentation/trace/index.rst b/Documentation/trace/index.rst index b7891cb1ab4d..47d6b466e308 100644 --- a/Documentation/trace/index.rst +++ b/Documentation/trace/index.rst @@ -19,6 +19,7 @@ Linux Tracing Technologies events-msr mmiotrace histogram + boottime-trace hwlat_detector intel_th stm