138 lines
3.4 KiB
Plaintext
138 lines
3.4 KiB
Plaintext
libtraceevent(3)
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================
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NAME
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----
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tep_data_type, tep_data_pid,tep_data_preempt_count, tep_data_flags -
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Extract common fields from a record.
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SYNOPSIS
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--------
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[verse]
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--
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*#include <event-parse.h>*
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enum *trace_flag_type* {
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_TRACE_FLAG_IRQS_OFF_,
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_TRACE_FLAG_IRQS_NOSUPPORT_,
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_TRACE_FLAG_NEED_RESCHED_,
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_TRACE_FLAG_HARDIRQ_,
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_TRACE_FLAG_SOFTIRQ_,
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};
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int *tep_data_type*(struct tep_handle pass:[*]_tep_, struct tep_record pass:[*]_rec_);
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int *tep_data_pid*(struct tep_handle pass:[*]_tep_, struct tep_record pass:[*]_rec_);
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int *tep_data_preempt_count*(struct tep_handle pass:[*]_tep_, struct tep_record pass:[*]_rec_);
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int *tep_data_flags*(struct tep_handle pass:[*]_tep_, struct tep_record pass:[*]_rec_);
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--
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DESCRIPTION
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-----------
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This set of functions can be used to extract common fields from a record.
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The _tep_data_type()_ function gets the event id from the record _rec_.
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It reads the "common_type" field. The _tep_ argument is the trace event parser
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context.
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The _tep_data_pid()_ function gets the process id from the record _rec_.
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It reads the "common_pid" field. The _tep_ argument is the trace event parser
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context.
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The _tep_data_preempt_count()_ function gets the preemption count from the
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record _rec_. It reads the "common_preempt_count" field. The _tep_ argument is
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the trace event parser context.
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The _tep_data_flags()_ function gets the latency flags from the record _rec_.
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It reads the "common_flags" field. The _tep_ argument is the trace event parser
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context. Supported latency flags are:
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[verse]
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--
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_TRACE_FLAG_IRQS_OFF_, Interrupts are disabled.
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_TRACE_FLAG_IRQS_NOSUPPORT_, Reading IRQ flag is not supported by the architecture.
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_TRACE_FLAG_NEED_RESCHED_, Task needs rescheduling.
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_TRACE_FLAG_HARDIRQ_, Hard IRQ is running.
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_TRACE_FLAG_SOFTIRQ_, Soft IRQ is running.
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--
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RETURN VALUE
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------------
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The _tep_data_type()_ function returns an integer, representing the event id.
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The _tep_data_pid()_ function returns an integer, representing the process id
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The _tep_data_preempt_count()_ function returns an integer, representing the
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preemption count.
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The _tep_data_flags()_ function returns an integer, representing the latency
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flags. Look at the _trace_flag_type_ enum for supported flags.
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All these functions in case of an error return a negative integer.
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EXAMPLE
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-------
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[source,c]
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--
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#include <event-parse.h>
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...
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struct tep_handle *tep = tep_alloc();
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...
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void process_record(struct tep_record *record)
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{
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int data;
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data = tep_data_type(tep, record);
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if (data >= 0) {
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/* Got the ID of the event */
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}
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data = tep_data_pid(tep, record);
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if (data >= 0) {
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/* Got the process ID */
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}
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data = tep_data_preempt_count(tep, record);
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if (data >= 0) {
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/* Got the preemption count */
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}
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data = tep_data_flags(tep, record);
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if (data >= 0) {
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/* Got the latency flags */
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}
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}
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...
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--
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FILES
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-----
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[verse]
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--
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*event-parse.h*
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Header file to include in order to have access to the library APIs.
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*-ltraceevent*
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Linker switch to add when building a program that uses the library.
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--
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SEE ALSO
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--------
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_libtraceevent(3)_, _trace-cmd(1)_
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AUTHOR
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------
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[verse]
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--
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*Steven Rostedt* <rostedt@goodmis.org>, author of *libtraceevent*.
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*Tzvetomir Stoyanov* <tz.stoyanov@gmail.com>, author of this man page.
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--
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REPORTING BUGS
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--------------
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Report bugs to <linux-trace-devel@vger.kernel.org>
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LICENSE
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-------
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libtraceevent is Free Software licensed under the GNU LGPL 2.1
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RESOURCES
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---------
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https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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