| Message ID | 20181106132035.7692-6-tstoyanov@vmware.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | libtracevent man pages | expand |
On Tue, 6 Nov 2018 13:20:54 +0000 Tzvetomir Stoyanov <tstoyanov@vmware.com> wrote: > This patch implements a man page, which documents > tep_is_latency_format() and tep_set_latency_format() > libtraceevent APIs > > Signed-off-by: Tzvetomir Stoyanov <tstoyanov@vmware.com> > --- > .../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 <event-parse.h>* > + > +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 The "big kernel lock" no longer exists (Yay!!!), we can remove that line. > +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. Hmm, perhaps we should change that parameter to true or false. > +Information is displayed with 6 characters. When a field is zero, or N/A, a pass:['.'] > +is printed. Example: > +[verse] > +-- > + <idle>-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. We need to add somewhere in this description about tep_print_event_task() and tep_print_event_time() which is what this affects. As tep_print_event*() creates the string to output and is affected by this format. We may change this before we release the final output. -- Steve > + > +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 <event-parse.h> > +... > +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* <rostedt@goodmis.org>, author of *libtraceevent*. > +*Tzvetomir Stoyanov* <tz.stoyanov@gmail.com>, author of this man page. > +-- > +REPORTING BUGS > +-------------- > +Report bugs to <linux-trace-devel@vger.kernel.org> > + > +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
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 <event-parse.h>* + +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] +-- + <idle>-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 <event-parse.h> +... +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* <rostedt@goodmis.org>, author of *libtraceevent*. +*Tzvetomir Stoyanov* <tz.stoyanov@gmail.com>, author of this man page. +-- +REPORTING BUGS +-------------- +Report bugs to <linux-trace-devel@vger.kernel.org> + +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
This patch implements a man page, which documents tep_is_latency_format() and tep_set_latency_format() libtraceevent APIs Signed-off-by: Tzvetomir Stoyanov <tstoyanov@vmware.com> --- .../libtraceevent-latency_format.txt | 98 +++++++++++++++++++ 1 file changed, 98 insertions(+) create mode 100644 tools/lib/traceevent/Documentation/libtraceevent-latency_format.txt