Tom Zanussi 4b147936fa tracing: Add support for 'synthetic' events ... Synthetic events are user-defined events generated from hist trigger variables saved from one or more other events. To define a synthetic event, the user writes a simple specification consisting of the name of the new event along with one or more variables and their type(s), to the tracing/synthetic_events file. For instance, the following creates a new event named 'wakeup_latency' with 3 fields: lat, pid, and prio: # echo 'wakeup_latency u64 lat; pid_t pid; int prio' >> \ /sys/kernel/debug/tracing/synthetic_events Reading the tracing/synthetic_events file lists all the currently-defined synthetic events, in this case the event we defined above: # cat /sys/kernel/debug/tracing/synthetic_events wakeup_latency u64 lat; pid_t pid; int prio At this point, the synthetic event is ready to use, and a histogram can be defined using it: # echo 'hist:keys=pid,prio,lat.log2:sort=pid,lat' >> \ /sys/kernel/debug/tracing/events/synthetic/wakeup_latency/trigger The new event is created under the tracing/events/synthetic/ directory and looks and behaves just like any other event: # ls /sys/kernel/debug/tracing/events/synthetic/wakeup_latency enable filter format hist id trigger Although a histogram can be defined for it, nothing will happen until an action tracing that event via the trace_synth() function occurs. The trace_synth() function is very similar to all the other trace_* invocations spread throughout the kernel, except in this case the trace_ function and its corresponding tracepoint isn't statically generated but defined by the user at run-time. How this can be automatically hooked up via a hist trigger 'action' is discussed in a subsequent patch. Link: http://lkml.kernel.org/r/c68df2284b7d172669daf9be29db62ad49bbc559.1516069914.git.tom.zanussi@linux.intel.com Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com> [fix noderef.cocci warnings, sizeof pointer for kcalloc of event->fields] Signed-off-by: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>		2018-03-10 16:05:58 -05:00
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blktrace.c
bpf_trace.c	bpf: fix bpf_prog_array_copy_to_user warning from perf event prog query	2018-02-14 08:59:37 -08:00
ftrace.c	ftrace: Remove incorrect setting of glob search field	2018-02-08 10:11:11 -05:00
Kconfig	Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net	2018-01-17 00:10:42 -05:00
Makefile
power-traces.c
ring_buffer_benchmark.c
ring_buffer.c	ring-buffer: Redefine the unimplemented RINGBUF_TYPE_TIME_STAMP	2018-03-10 16:05:50 -05:00
rpm-traces.c
trace_benchmark.c
trace_benchmark.h
trace_branch.c
trace_clock.c
trace_entries.h
trace_event_perf.c
trace_events_filter_test.h
trace_events_filter.c	tracing: Fix parsing of globs with a wildcard at the beginning	2018-02-08 10:11:47 -05:00
trace_events_hist.c	tracing: Add support for 'synthetic' events	2018-03-10 16:05:58 -05:00
trace_events_trigger.c	tracing: Add variable reference handling to hist triggers	2018-03-10 16:05:58 -05:00
trace_events.c	tracing: Make sure the parsed string always terminates with '\0'	2018-01-23 15:57:28 -05:00
trace_export.c
trace_functions_graph.c
trace_functions.c	tracing: Update stack trace skipping for ORC unwinder	2018-01-23 15:57:00 -05:00
trace_hwlat.c
trace_irqsoff.c
trace_kdb.c
trace_kprobe.c	error-injection: Separate error-injection from kprobe	2018-01-12 17:33:38 -08:00
trace_mmiotrace.c
trace_nop.c
trace_output.c
trace_output.h
trace_printk.c
trace_probe.c
trace_probe.h
trace_sched_switch.c
trace_sched_wakeup.c
trace_selftest_dynamic.c	ftrace: Mark function tracer test functions noinline/noclone	2018-01-23 15:57:29 -05:00
trace_selftest.c
trace_seq.c
trace_stack.c
trace_stat.c
trace_stat.h
trace_syscalls.c
trace_uprobe.c	trace_uprobe: Display correct offset in uprobe_events	2018-01-23 15:57:29 -05:00
trace.c	tracing: Add variable reference handling to hist triggers	2018-03-10 16:05:58 -05:00
trace.h	tracing: Add variable reference handling to hist triggers	2018-03-10 16:05:58 -05:00
tracing_map.c	tracing: Add per-element variable support to tracing_map	2018-03-10 16:05:53 -05:00
tracing_map.h	tracing: Add per-element variable support to tracing_map	2018-03-10 16:05:53 -05:00