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Commit dc231032 authored by Namhyung Kim's avatar Namhyung Kim Committed by Arnaldo Carvalho de Melo
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perf ftrace: Add support for -a and -C option 



The -a/--all-cpus and -C/--cpu option is for controlling tracing cpus.

Signed-off-by: default avatarNamhyung Kim <namhyung@kernel.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: kernel-team@lge.com
Link: http://lkml.kernel.org/r/20170224011251.14946-3-namhyung@kernel.org


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 4400ac8a

tools/perf/Documentation/perf-ftrace.txt

+14 −0
Original line number Diff line number Diff line
@@ -34,6 +34,20 @@ OPTIONS 
--pid=::

	Trace on existing process id (comma separated list).



-a::

--all-cpus::

	Force system-wide collection.  Scripts run without a <command>

	normally use -a by default, while scripts run with a <command>

	normally don't - this option allows the latter to be run in

	system-wide mode.



-C::

--cpu=::

	Only trace for the list of CPUs provided.  Multiple CPUs can

	be provided as a comma separated list with no space like: 0,1.

	Ranges of CPUs are specified with -: 0-2.

	Default is to trace on all online CPUs.





SEE ALSO

--------

tools/perf/builtin-ftrace.c

+60 −0
Original line number Diff line number Diff line
@@ -17,6 +17,7 @@ 
#include <subcmd/parse-options.h>

#include "evlist.h"

#include "target.h"

#include "cpumap.h"

#include "thread_map.h"

#include "util/config.h"
@@ -96,6 +97,8 @@ static int append_tracing_file(const char *name, const char *val) 
	return __write_tracing_file(name, val, true);

}



static int reset_tracing_cpu(void);



static int reset_tracing_files(struct perf_ftrace *ftrace __maybe_unused)

{

	if (write_tracing_file("tracing_on", "0") < 0)
@@ -107,6 +110,9 @@ static int reset_tracing_files(struct perf_ftrace *ftrace __maybe_unused) 
	if (write_tracing_file("set_ftrace_pid", " ") < 0)

		return -1;



	if (reset_tracing_cpu() < 0)

		return -1;



	return 0;

}
@@ -127,6 +133,51 @@ static int set_tracing_pid(struct perf_ftrace *ftrace) 
	return 0;

}



static int set_tracing_cpumask(struct cpu_map *cpumap)

{

	char *cpumask;

	size_t mask_size;

	int ret;

	int last_cpu;



	last_cpu = cpu_map__cpu(cpumap, cpumap->nr - 1);

	mask_size = (last_cpu + 3) / 4 + 1;

	mask_size += last_cpu / 32; /* ',' is needed for every 32th cpus */



	cpumask = malloc(mask_size);

	if (cpumask == NULL) {

		pr_debug("failed to allocate cpu mask\n");

		return -1;

	}



	cpu_map__snprint_mask(cpumap, cpumask, mask_size);



	ret = write_tracing_file("tracing_cpumask", cpumask);



	free(cpumask);

	return ret;

}



static int set_tracing_cpu(struct perf_ftrace *ftrace)

{

	struct cpu_map *cpumap = ftrace->evlist->cpus;



	if (!target__has_cpu(&ftrace->target))

		return 0;



	return set_tracing_cpumask(cpumap);

}



static int reset_tracing_cpu(void)

{

	struct cpu_map *cpumap = cpu_map__new(NULL);

	int ret;



	ret = set_tracing_cpumask(cpumap);

	cpu_map__put(cpumap);

	return ret;

}



static int __cmd_ftrace(struct perf_ftrace *ftrace, int argc, const char **argv)

{

	char *trace_file;
@@ -163,6 +214,11 @@ static int __cmd_ftrace(struct perf_ftrace *ftrace, int argc, const char **argv) 
		goto out_reset;

	}



	if (set_tracing_cpu(ftrace) < 0) {

		pr_err("failed to set tracing cpumask\n");

		goto out_reset;

	}



	if (write_tracing_file("current_tracer", ftrace->tracer) < 0) {

		pr_err("failed to set current_tracer to %s\n", ftrace->tracer);

		goto out_reset;
@@ -264,6 +320,10 @@ int cmd_ftrace(int argc, const char **argv, const char *prefix __maybe_unused) 
		   "trace on existing process id"),

	OPT_INCR('v', "verbose", &verbose,

		 "be more verbose"),

	OPT_BOOLEAN('a', "all-cpus", &ftrace.target.system_wide,

		    "system-wide collection from all CPUs"),

	OPT_STRING('C', "cpu", &ftrace.target.cpu_list, "cpu",

		    "list of cpus to monitor"),

	OPT_END()

	};