From patchwork Fri Apr 12 13:37:45 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tzvetomir Stoyanov X-Patchwork-Id: 10898319 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 63FE21515 for ; Fri, 12 Apr 2019 13:38:20 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 485FA28D7F for ; Fri, 12 Apr 2019 13:38:20 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 472DC288BB; Fri, 12 Apr 2019 13:38:20 +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 46EA428ED5 for ; Fri, 12 Apr 2019 13:38:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726921AbfDLNiS (ORCPT ); Fri, 12 Apr 2019 09:38:18 -0400 Received: from mail-wm1-f65.google.com ([209.85.128.65]:55454 "EHLO mail-wm1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726907AbfDLNiS (ORCPT ); Fri, 12 Apr 2019 09:38:18 -0400 Received: by mail-wm1-f65.google.com with SMTP id o25so11274359wmf.5 for ; Fri, 12 Apr 2019 06:38:17 -0700 (PDT) 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=FLXNULcmM8V+HAfXfH+q1nJkgQ2LtsvRkPzQ0znRZiU=; b=o2VTb0w5o3zTrQIgWTssnbaegZPYxW9e7M/MLYqtAj3qu+R9giq9A8eUsvZydJhe9v 4DqXBxCWtj/lJzl1PxJDBLIl9BZkJefjOAE9aR0GN7M6Q1UEHLrqD4oIWRZ2TeJTEqVP c241z127MnjedT+vyqXkInTvZRL9YwFlWYtQw675IDqHV3H4vhSrf1Yj4slenodYGhf7 igCtrUkY8Izc0QRiCunxDE12y6oI/UBUHIUDJBfoWKT8xV5xtFPgQXNoZ0Wrd/4o+fT0 wSgWThZ86RFD5iVFkqbaUvjgHyCaYH6BSq+Udw8J9bFVrOQ34BhPNt8kx59m69vLFSns EP5g== X-Gm-Message-State: APjAAAWvzldkoogtH5lPYcVNK7LpKSP6TK2fozmYVyu34tFKpsHYWY/7 0mjdQq+8tpe+3wGFOIt5kSg= X-Google-Smtp-Source: APXvYqwb30Syf225Lr9NOd5NWIMwYrS3CWTKQs52pMItMPf+YcJASBU2xmiKdJNHL+OIDlMjbmammw== X-Received: by 2002:a1c:c504:: with SMTP id v4mr11591509wmf.45.1555076296460; Fri, 12 Apr 2019 06:38:16 -0700 (PDT) Received: from oberon.eng.vmware.com ([146.247.46.5]) by smtp.gmail.com with ESMTPSA id x205sm11594682wmg.9.2019.04.12.06.38.15 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Fri, 12 Apr 2019 06:38:15 -0700 (PDT) From: Tzvetomir Stoyanov To: rostedt@goodmis.org Cc: linux-trace-devel@vger.kernel.org Subject: [PATCH v5 04/30] tools/lib/traceevent: Man page for header_page APIs Date: Fri, 12 Apr 2019 16:37:45 +0300 Message-Id: <20190412133811.15878-5-tstoyanov@vmware.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190412133811.15878-1-tstoyanov@vmware.com> References: <20190412133811.15878-1-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 a man page for libtraceevent APIs: tep_get_header_page_size(), tep_get_header_timestamp_size(), tep_is_old_format() Signed-off-by: Tzvetomir Stoyanov --- .../libtraceevent-header_page.txt | 105 ++++++++++++++++++ 1 file changed, 105 insertions(+) create mode 100644 tools/lib/traceevent/Documentation/libtraceevent-header_page.txt diff --git a/tools/lib/traceevent/Documentation/libtraceevent-header_page.txt b/tools/lib/traceevent/Documentation/libtraceevent-header_page.txt new file mode 100644 index 000000000000..e1bd664ac123 --- /dev/null +++ b/tools/lib/traceevent/Documentation/libtraceevent-header_page.txt @@ -0,0 +1,105 @@ +libtraceevent(3) +================ + +NAME +---- +tep_get_header_page_size, tep_get_header_timestamp_size, tep_is_old_format - +Get the data stored in the header page, in kernel context. + +SYNOPSIS +-------- +[verse] +-- +*#include * + +int *tep_get_header_page_size*(struct tep_handle pass:[*]_tep_); +int *tep_get_header_timestamp_size*(struct tep_handle pass:[*]_tep_); +bool *tep_is_old_format*(struct tep_handle pass:[*]_tep_); +-- +DESCRIPTION +----------- +These functions retrieve information from kernel context, stored in +/sys/kernel/debug/tracing/events/header_page. Old kernels do not have header +page info, so default values from user space context are used. + +The _tep_get_header_page_size()_ function returns the size of a long integer, +in kernel context. The _tep_ argument is trace event parser context. +This information is retrieved from /sys/kernel/debug/tracing/events/header_page, + "commit" field. + +The _tep_get_header_timestamp_size()_ function returns the size of timestamps, +in kernel context. The _tep_ argument is trace event parser context. +This information is retrieved from /sys/kernel/debug/tracing/events/header_page, + "timestamp" field. + +The _tep_is_old_format()_ function returns if the kernel is old one and has no +/sys/kernel/debug/tracing/events/header_page. + +RETURN VALUE +------------ +The _tep_get_header_page_size()_ function returns the size of a long integer, +in bytes. + +The _tep_get_header_timestamp_size()_ function returns the size of timestamps, +in bytes. + +The _tep_is_old_format()_ function returns true, if an old kernel is used to +generate the tracing data, which has no +/sys/kernel/debug/tracing/events/header_page. If the kernel is new, or _tep_ is +NULL, false is returned. + +EXAMPLE +------- +[source,c] +-- +#include +... +struct tep_handle *tep = tep_alloc(); +... + int longsize; + int timesize; + bool old; + + longsize = tep_get_header_page_size(tep); + timesize = tep_get_header_timestamp_size(tep); + old = tep_is_old_format(tep); + + printf ("%s kernel is used to generate the tracing data.\n", + old?"Old":"New"); + printf("The size of a long integer is %d bytes.\n", longsize); + printf("The timestamps size is %d bytes.\n", timesize); +... +-- + +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)_ + +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