Merge branch 'tracing/core' of... (d28daf92) · Commits · EulixOS / Software / Kernel

Documentation/trace/ftrace.txt

+36 −32

Original line number	Original line	Diff line number	Diff line
	@@ -85,26 +85,19 @@ of ftrace. Here is a list of some of the key files:
	This file holds the output of the trace in a human		This file holds the output of the trace in a human
	readable format (described below).		readable format (described below).

	latency_trace:

	This file shows the same trace but the information
	is organized more to display possible latencies
	in the system (described below).

	trace_pipe:		trace_pipe:

	The output is the same as the "trace" file but this		The output is the same as the "trace" file but this
	file is meant to be streamed with live tracing.		file is meant to be streamed with live tracing.
	Reads from this file will block until new data		Reads from this file will block until new data is
	is retrieved. Unlike the "trace" and "latency_trace"		retrieved. Unlike the "trace" file, this file is a
	files, this file is a consumer. This means reading		consumer. This means reading from this file causes
	from this file causes sequential reads to display		sequential reads to display more current data. Once
	more current data. Once data is read from this		data is read from this file, it is consumed, and
	file, it is consumed, and will not be read		will not be read again with a sequential read. The
	again with a sequential read. The "trace" and		"trace" file is static, and if the tracer is not
	"latency_trace" files are static, and if the		adding more data,they will display the same
	tracer is not adding more data, they will display		information every time they are read.
	the same information every time they are read.

	trace_options:		trace_options:

	@@ -117,10 +110,10 @@ of ftrace. Here is a list of some of the key files:
	Some of the tracers record the max latency.		Some of the tracers record the max latency.
	For example, the time interrupts are disabled.		For example, the time interrupts are disabled.
	This time is saved in this file. The max trace		This time is saved in this file. The max trace
	will also be stored, and displayed by either		will also be stored, and displayed by "trace".
	"trace" or "latency_trace". A new max trace will		A new max trace will only be recorded if the
	only be recorded if the latency is greater than		latency is greater than the value in this
	the value in this file. (in microseconds)		file. (in microseconds)

	buffer_size_kb:		buffer_size_kb:

	@@ -210,7 +203,7 @@ Here is the list of current tracers that may be configured.
	the trace with the longest max latency.		the trace with the longest max latency.
	See tracing_max_latency. When a new max is recorded,		See tracing_max_latency. When a new max is recorded,
	it replaces the old trace. It is best to view this		it replaces the old trace. It is best to view this
	trace via the latency_trace file.		trace with the latency-format option enabled.

	"preemptoff"		"preemptoff"

	@@ -307,8 +300,8 @@ the lowest priority thread (pid 0).
	Latency trace format		Latency trace format
	--------------------		--------------------

	For traces that display latency times, the latency_trace file		When the latency-format option is enabled, the trace file gives
	gives somewhat more information to see why a latency happened.		somewhat more information to see why a latency happened.
	Here is a typical trace.		Here is a typical trace.

	# tracer: irqsoff		# tracer: irqsoff
	@@ -380,9 +373,10 @@ explains which is which.

	The above is mostly meaningful for kernel developers.		The above is mostly meaningful for kernel developers.

	time: This differs from the trace file output. The trace file output		time: When the latency-format option is enabled, the trace file
	includes an absolute timestamp. The timestamp used by the		output includes a timestamp relative to the start of the
	latency_trace file is relative to the start of the trace.		trace. This differs from the output when latency-format
			is disabled, which includes an absolute timestamp.

	delay: This is just to help catch your eye a bit better. And		delay: This is just to help catch your eye a bit better. And
	needs to be fixed to be only relative to the same CPU.		needs to be fixed to be only relative to the same CPU.
	@@ -440,7 +434,8 @@ Here are the available options:
	sym-addr:		sym-addr:
	bash-4000 [01] 1477.606694: simple_strtoul <c0339346>		bash-4000 [01] 1477.606694: simple_strtoul <c0339346>

	verbose - This deals with the latency_trace file.		verbose - This deals with the trace file when the
			latency-format option is enabled.

	bash 4000 1 0 00000000 00010a95 [58127d26] 1720.415ms \		bash 4000 1 0 00000000 00010a95 [58127d26] 1720.415ms \
	(+0.000ms): simple_strtoul (strict_strtoul)		(+0.000ms): simple_strtoul (strict_strtoul)
	@@ -472,7 +467,7 @@ Here are the available options:
	the app is no longer running		the app is no longer running

	The lookup is performed when you read		The lookup is performed when you read
	trace,trace_pipe,latency_trace. Example:		trace,trace_pipe. Example:

	a.out-1623 [000] 40874.465068: /root/a.out[+0x480] <-/root/a.out[+0		a.out-1623 [000] 40874.465068: /root/a.out[+0x480] <-/root/a.out[+0
	x494] <- /root/a.out[+0x4a8] <- /lib/libc-2.7.so[+0x1e1a6]		x494] <- /root/a.out[+0x4a8] <- /lib/libc-2.7.so[+0x1e1a6]
	@@ -481,6 +476,11 @@ x494] <- /root/a.out[+0x4a8] <- /lib/libc-2.7.so[+0x1e1a6]
	every scheduling event. Will add overhead if		every scheduling event. Will add overhead if
	there's a lot of tasks running at once.		there's a lot of tasks running at once.

			latency-format - This option changes the trace. When
			it is enabled, the trace displays
			additional information about the
			latencies, as described in "Latency
			trace format".

	sched_switch		sched_switch
	------------		------------
	@@ -596,12 +596,13 @@ To reset the maximum, echo 0 into tracing_max_latency. Here is
	an example:		an example:

	# echo irqsoff > current_tracer		# echo irqsoff > current_tracer
			# echo latency-format > trace_options
	# echo 0 > tracing_max_latency		# echo 0 > tracing_max_latency
	# echo 1 > tracing_enabled		# echo 1 > tracing_enabled
	# ls -ltr		# ls -ltr
	[...]		[...]
	# echo 0 > tracing_enabled		# echo 0 > tracing_enabled
	# cat latency_trace		# cat trace
	# tracer: irqsoff		# tracer: irqsoff
	#		#
	irqsoff latency trace v1.1.5 on 2.6.26		irqsoff latency trace v1.1.5 on 2.6.26
	@@ -703,12 +704,13 @@ which preemption was disabled. The control of preemptoff tracer
	is much like the irqsoff tracer.		is much like the irqsoff tracer.

	# echo preemptoff > current_tracer		# echo preemptoff > current_tracer
			# echo latency-format > trace_options
	# echo 0 > tracing_max_latency		# echo 0 > tracing_max_latency
	# echo 1 > tracing_enabled		# echo 1 > tracing_enabled
	# ls -ltr		# ls -ltr
	[...]		[...]
	# echo 0 > tracing_enabled		# echo 0 > tracing_enabled
	# cat latency_trace		# cat trace
	# tracer: preemptoff		# tracer: preemptoff
	#		#
	preemptoff latency trace v1.1.5 on 2.6.26-rc8		preemptoff latency trace v1.1.5 on 2.6.26-rc8
	@@ -850,12 +852,13 @@ Again, using this trace is much like the irqsoff and preemptoff
	tracers.		tracers.

	# echo preemptirqsoff > current_tracer		# echo preemptirqsoff > current_tracer
			# echo latency-format > trace_options
	# echo 0 > tracing_max_latency		# echo 0 > tracing_max_latency
	# echo 1 > tracing_enabled		# echo 1 > tracing_enabled
	# ls -ltr		# ls -ltr
	[...]		[...]
	# echo 0 > tracing_enabled		# echo 0 > tracing_enabled
	# cat latency_trace		# cat trace
	# tracer: preemptirqsoff		# tracer: preemptirqsoff
	#		#
	preemptirqsoff latency trace v1.1.5 on 2.6.26-rc8		preemptirqsoff latency trace v1.1.5 on 2.6.26-rc8
	@@ -1012,11 +1015,12 @@ Instead of performing an 'ls', we will run 'sleep 1' under
	'chrt' which changes the priority of the task.		'chrt' which changes the priority of the task.

	# echo wakeup > current_tracer		# echo wakeup > current_tracer
			# echo latency-format > trace_options
	# echo 0 > tracing_max_latency		# echo 0 > tracing_max_latency
	# echo 1 > tracing_enabled		# echo 1 > tracing_enabled
	# chrt -f 5 sleep 1		# chrt -f 5 sleep 1
	# echo 0 > tracing_enabled		# echo 0 > tracing_enabled
	# cat latency_trace		# cat trace
	# tracer: wakeup		# tracer: wakeup
	#		#
	wakeup latency trace v1.1.5 on 2.6.26-rc8		wakeup latency trace v1.1.5 on 2.6.26-rc8

kernel/trace/trace_events_filter.c

+6 −5

Original line number	Original line	Diff line number	Diff line
	@@ -409,6 +409,9 @@ static int init_preds(struct ftrace_event_call *call)
	struct filter_pred *pred;		struct filter_pred *pred;
	int i;		int i;

			if (call->filter)
			return 0;

	filter = call->filter = kzalloc(sizeof(*filter), GFP_KERNEL);		filter = call->filter = kzalloc(sizeof(*filter), GFP_KERNEL);
	if (!call->filter)		if (!call->filter)
	return -ENOMEM;		return -ENOMEM;
	@@ -447,12 +450,10 @@ static int init_subsystem_preds(struct event_subsystem *system)
	if (strcmp(call->system, system->name) != 0)		if (strcmp(call->system, system->name) != 0)
	continue;		continue;

	if (!call->filter) {
	err = init_preds(call);		err = init_preds(call);
	if (err)		if (err)
	return err;		return err;
	}		}
	}

	return 0;		return 0;
	}		}