From patchwork Fri Nov 9 13:31:56 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tzvetomir Stoyanov X-Patchwork-Id: 10759711 Return-Path: Received: from mail-eopbgr810079.outbound.protection.outlook.com ([40.107.81.79]:10688 "EHLO NAM01-BY2-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727800AbeKIXMl (ORCPT ); Fri, 9 Nov 2018 18:12:41 -0500 From: Tzvetomir Stoyanov To: "rostedt@goodmis.org" CC: "linux-trace-devel@vger.kernel.org" Subject: [PATCH v2 09/11] tools/lib/traceevent: Man page for tep_is_latency_format() and tep_set_latency_format() Date: Fri, 9 Nov 2018 13:31:56 +0000 Message-ID: <20181109133135.25804-9-tstoyanov@vmware.com> References: <20181109133135.25804-1-tstoyanov@vmware.com> In-Reply-To: <20181109133135.25804-1-tstoyanov@vmware.com> Content-Language: en-US MIME-Version: 1.0 Sender: linux-trace-devel-owner@vger.kernel.org List-ID: Content-Length: 3716 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 | 100 ++++++++++++++++++ 1 file changed, 100 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..4b0d7d3f6ae9 --- /dev/null +++ b/tools/lib/traceevent/Documentation/libtraceevent-latency_format.txt @@ -0,0 +1,100 @@ +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']. + +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. + +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