From patchwork Fri Mar 8 13:36:18 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tzvetomir Stoyanov X-Patchwork-Id: 10844773 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id E6E8E17E9 for ; Fri, 8 Mar 2019 13:37:09 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id D339C2E40A for ; Fri, 8 Mar 2019 13:37:09 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id C78772E440; Fri, 8 Mar 2019 13:37:09 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 490032E40A for ; Fri, 8 Mar 2019 13:37:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726675AbfCHNhJ (ORCPT ); Fri, 8 Mar 2019 08:37:09 -0500 Received: from mail-wm1-f66.google.com ([209.85.128.66]:53910 "EHLO mail-wm1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726601AbfCHNhJ (ORCPT ); Fri, 8 Mar 2019 08:37:09 -0500 Received: by mail-wm1-f66.google.com with SMTP id e74so12566363wmg.3 for ; Fri, 08 Mar 2019 05:37:07 -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=e+1D0rjAi1cZiOqo1mIduUIu3Cyi19E08jFbilxQE2w=; b=hfkF/Cjc9Bs6li8jSCIODJazAESY8WRXUz0vSq+g+vucnH6m1SeTlJNmSugV3N8be8 qXK35N9YarMpWJBFmUQYif5KUwdO6sQ+H6BntXzrQqBgbfSP1pr2DTX9dYWnZGJOlWHL WMy/ZYhLzuETZmIkec7Kqlk3FuLziuxvSaAaJW+/lvLlX1xHjujri99f3h+8vpfkgL6v 2hhGNdBAeHN4U929fUzTtbQj/dvHjEi6a3yHyW1bBIBlkuCtKes7bwy7le68RCWHAljv zoGaqtTS5lN05RsvG9DDxqCQ10bdsJu4gfuzdjWS/u/EoOmdnd8wU+odFz4t+I4ZGUb3 BE6A== X-Gm-Message-State: APjAAAVfDY3ymO1t9I6+XpmUWTvoghP0yWfg5DZXw96HYJtNoxA1AHlk K4+FnvBRAAutGmro9z0+U1o= X-Google-Smtp-Source: APXvYqxj7SARtIhxgn4jL8AV/yPQgnm4xwcfdQMshoUV87FTJnoSXT0PDmrbNkIJCSVdbL5T3TQWhg== X-Received: by 2002:a1c:5f86:: with SMTP id t128mr9075252wmb.87.1552052227038; Fri, 08 Mar 2019 05:37:07 -0800 (PST) Received: from oberon.eng.vmware.com ([146.247.46.5]) by smtp.gmail.com with ESMTPSA id 132sm19625364wmd.27.2019.03.08.05.37.06 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Fri, 08 Mar 2019 05:37:06 -0800 (PST) From: Tzvetomir Stoyanov To: rostedt@goodmis.org Cc: linux-trace-devel@vger.kernel.org Subject: [PATCH v4 10/46] tools/lib/traceevent: Man page for tep_is_latency_format() and tep_set_latency_format() Date: Fri, 8 Mar 2019 15:36:18 +0200 Message-Id: <20190308133654.21264-11-tstoyanov@vmware.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190308133654.21264-1-tstoyanov@vmware.com> References: <20190308133654.21264-1-tstoyanov@vmware.com> MIME-Version: 1.0 Sender: linux-trace-devel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-trace-devel@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Create man pages for tep_is_latency_format() and tep_set_latency_format() as part of the libtraceevent APIs. Signed-off-by: Tzvetomir Stoyanov --- .../libtraceevent-latency_format.txt | 140 ++++++++++++++++++ 1 file changed, 140 insertions(+) create mode 100644 tools/lib/traceevent/Documentation/libtraceevent-latency_format.txt diff --git a/tools/lib/traceevent/Documentation/libtraceevent-latency_format.txt b/tools/lib/traceevent/Documentation/libtraceevent-latency_format.txt new file mode 100644 index 000000000000..ea82cbda7b7c --- /dev/null +++ b/tools/lib/traceevent/Documentation/libtraceevent-latency_format.txt @@ -0,0 +1,140 @@ +libtraceevent(3) +================ + +NAME +---- +tep_set_latency_format,tep_is_latency_format - Get / set "latency output" format. + +SYNOPSIS +-------- +[verse] +-- +*#include * + +void *tep_set_latency_format*(struct tep_handle pass:[*]_tep_, int _lat_); +int *tep_is_latency_format*(struct tep_handle pass:[*]_tep_); + +-- + +DESCRIPTION +----------- +"Latency output" format prints information about interrupts being disabled, +soft irq being disabled, the "need_resched" flag being set and preempt count. +This information is recorded with every event, but by default is not printed. + +The _tep_set_latency_format()_ function enables the "latency output" printing. +The _tep_ argument is trace event parser context. The _lat_ argument can be zero, +for "latency output" disabled, or non zero for "latency output" enabled. +Information is displayed with 6 characters. When a field is zero, or N/A, a pass:['.'] +is printed. Example: +[verse] +-- + -0 0d.h1. 106467.859747: function: ktime_get <-- tick_check_idle +-- +The 0d.h1. denotes this information. The first character is never a pass:['.'] +and represents what CPU the trace was recorded on (CPU 0). The pass:['d'] denotes +that interrupts were disabled. The pass:['h'] means that this was called inside +an interrupt handler. The pass:['1'] is the preemption disabled (preempt_count) +was set to one. The two pass:['.']s are "need_resched" flag and kernel lock +counter. If the "need_resched" flag is set, then that character would be a pass:['N']. +See 'LATENCY FORMAT' section. + +The _tep_is_latency_format()_ function returns if "latency output" is enabled. + +This "Latency output" setting affects output of _tep_print_event_task()_ +and _tep_print_event_time()_ APIs. + +LATENCY FORMAT +-------------- +The latency format displays 5 or more fields: +[verse] +-- + CPU #, interrupt state, scheduling state, current context, and preemption count. + + Field 1 is the CPU number (starting with zero). + + Field 2 is the interrupt enabled state: + d : Interrupts are disabled + . : Interrupts are enabled + X : The architecture does not support this information + + Field 3 is the "need resched" state. + N : The task is set to call the scheduler when possible, as another + higher priority task may need to be scheduled in. + . : The task is not set to call the scheduler. + + Field 4 is the context state. + . : Normal context + s : Soft interrupt context + h : Hard interrupt context + H : Hard interrupt context which triggered during soft interrupt context. + z : NMI context + Z : NMI context which triggered during hard interrupt context + + Field 5 is the preemption count. + . : The preempt count is zero. + + On preemptible kernels (where the task can be scheduled out in + arbitrary locations while in kernel context), The preempt count, + when non zero, will prevent the kernel from scheduling out the + current task. The preempt count number is displayed when it is not + zero. +-- +Depending on the kernel, it may show other fields (lock depth, +or migration disabled, which are unique to specialized kernels). + +RETURN VALUE +------------ + +The _tep_is_latency_format()_ function returns non zero if "latency output" +is enabled, or zero if it is disabled. + +EXAMPLE +------- +[source,c] +-- +#include +... +struct tep_handle *tep = tep_alloc(); +... + tep_set_latency_format(tep, 1); +... + if (tep_is_latency_format(tep)) { + /* latency output format is enabled */ + } else { + /* latency output format is disabled */ + } +-- + +FILES +----- +[verse] +-- +*event-parse.h* + Header file to include in order to have access to the library APIs. +*-ltraceevent* + Linker switch to add when building a program that uses the library. +-- + +SEE ALSO +-------- +_libtraceevent(3)_, _trace-cmd(1)_, tep_print_event_task(3), tep_print_event_time(3) + +AUTHOR +------ +[verse] +-- +*Steven Rostedt* , author of *libtraceevent*. +*Tzvetomir Stoyanov* , author of this man page. +-- +REPORTING BUGS +-------------- +Report bugs to + +LICENSE +------- +libtraceevent is Free Software licensed under the GNU LGPL 2.1 + +RESOURCES +--------- +https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git