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Diffstat (limited to 'tools/lib')
| -rw-r--r-- | tools/lib/traceevent/Documentation/libtraceevent-record_parse.txt | 137 |
1 files changed, 137 insertions, 0 deletions
diff --git a/tools/lib/traceevent/Documentation/libtraceevent-record_parse.txt b/tools/lib/traceevent/Documentation/libtraceevent-record_parse.txt new file mode 100644 index 000000000000..e9a69116c78b --- /dev/null +++ b/tools/lib/traceevent/Documentation/libtraceevent-record_parse.txt @@ -0,0 +1,137 @@ +libtraceevent(3) +================ + +NAME +---- +tep_data_type, tep_data_pid,tep_data_preempt_count, tep_data_flags - +Extract common fields from a record. + +SYNOPSIS +-------- +[verse] +-- +*#include <event-parse.h>* + +enum *trace_flag_type* { + _TRACE_FLAG_IRQS_OFF_, + _TRACE_FLAG_IRQS_NOSUPPORT_, + _TRACE_FLAG_NEED_RESCHED_, + _TRACE_FLAG_HARDIRQ_, + _TRACE_FLAG_SOFTIRQ_, +}; + +int *tep_data_type*(struct tep_handle pass:[*]_tep_, struct tep_record pass:[*]_rec_); +int *tep_data_pid*(struct tep_handle pass:[*]_tep_, struct tep_record pass:[*]_rec_); +int *tep_data_preempt_count*(struct tep_handle pass:[*]_tep_, struct tep_record pass:[*]_rec_); +int *tep_data_flags*(struct tep_handle pass:[*]_tep_, struct tep_record pass:[*]_rec_); +-- + +DESCRIPTION +----------- +This set of functions can be used to extract common fields from a record. + +The _tep_data_type()_ function gets the event id from the record _rec_. +It reads the "common_type" field. The _tep_ argument is the trace event parser +context. + +The _tep_data_pid()_ function gets the process id from the record _rec_. +It reads the "common_pid" field. The _tep_ argument is the trace event parser +context. + +The _tep_data_preempt_count()_ function gets the preemption count from the +record _rec_. It reads the "common_preempt_count" field. The _tep_ argument is +the trace event parser context. + +The _tep_data_flags()_ function gets the latency flags from the record _rec_. +It reads the "common_flags" field. The _tep_ argument is the trace event parser +context. Supported latency flags are: +[verse] +-- + _TRACE_FLAG_IRQS_OFF_, Interrupts are disabled. + _TRACE_FLAG_IRQS_NOSUPPORT_, Reading IRQ flag is not supported by the architecture. + _TRACE_FLAG_NEED_RESCHED_, Task needs rescheduling. + _TRACE_FLAG_HARDIRQ_, Hard IRQ is running. + _TRACE_FLAG_SOFTIRQ_, Soft IRQ is running. +-- + +RETURN VALUE +------------ +The _tep_data_type()_ function returns an integer, representing the event id. + +The _tep_data_pid()_ function returns an integer, representing the process id + +The _tep_data_preempt_count()_ function returns an integer, representing the +preemption count. + +The _tep_data_flags()_ function returns an integer, representing the latency +flags. Look at the _trace_flag_type_ enum for supported flags. + +All these functions in case of an error return a negative integer. + +EXAMPLE +------- +[source,c] +-- +#include <event-parse.h> +... +struct tep_handle *tep = tep_alloc(); +... +void process_record(struct tep_record *record) +{ + int data; + + data = tep_data_type(tep, record); + if (data >= 0) { + /* Got the ID of the event */ + } + + data = tep_data_pid(tep, record); + if (data >= 0) { + /* Got the process ID */ + } + + data = tep_data_preempt_count(tep, record); + if (data >= 0) { + /* Got the preemption count */ + } + + data = tep_data_flags(tep, record); + if (data >= 0) { + /* Got the latency flags */ + } +} +... +-- + +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 |