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: Namhyung 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: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/Documentation/perf-ftrace.txt b/tools/perf/Documentation/perf-ftrace.txt
index 2d39397f3f301b561d3c7eadab9fc3055cde7ae8..6e6a8b22c8594f42e9727c81a8e4b4adc8301e43 100644 (file)
--- a/tools/perf/Documentation/perf-ftrace.txt
+++ b/tools/perf/Documentation/perf-ftrace.txt
@@ -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
 --------

diff --git a/tools/perf/builtin-ftrace.c b/tools/perf/builtin-ftrace.c
index 85eee9c444ae3b85172796e0bb2137b2a1100226..d5b566ed7178450fbc1b00b37addc58ef5014c9a 100644 (file)
--- a/tools/perf/builtin-ftrace.c
+++ b/tools/perf/builtin-ftrace.c
@@ -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()
        };