From patchwork Tue Nov 6 13:20:54 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tzvetomir Stoyanov X-Patchwork-Id: 10759667 Return-Path: Received: from mail-eopbgr710057.outbound.protection.outlook.com ([40.107.71.57]:57353 "EHLO NAM05-BY2-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S2388116AbeKFWqI (ORCPT ); Tue, 6 Nov 2018 17:46:08 -0500 From: Tzvetomir Stoyanov To: "rostedt@goodmis.org" CC: "linux-trace-devel@vger.kernel.org" Subject: [PATCH 5/7] tools/lib/traceevent: Implement libtraceevent man pages Date: Tue, 6 Nov 2018 13:20:54 +0000 Message-ID: <20181106132035.7692-6-tstoyanov@vmware.com> References: <20181106132035.7692-1-tstoyanov@vmware.com> In-Reply-To: <20181106132035.7692-1-tstoyanov@vmware.com> Content-Language: en-US MIME-Version: 1.0 Sender: linux-trace-devel-owner@vger.kernel.org List-ID: Content-Length: 3582 This patch implements a man page, which documents tep_is_latency_format() and tep_set_latency_format() libtraceevent APIs Signed-off-by: Tzvetomir Stoyanov --- .../libtraceevent-latency_format.txt | 98 +++++++++++++++++++ 1 file changed, 98 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..a7eaed5d1a7e --- /dev/null +++ b/tools/lib/traceevent/Documentation/libtraceevent-latency_format.txt @@ -0,0 +1,98 @@ +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, preempt count, +and big kernel lock. 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']. + +The _tep_is_latency_format()_ function returns if "latency output" is enabled. + +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)_ + +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