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Subject[PATCH 06/17] perf ftrace: Split "live" sub-command
Date
From: Namhyung Kim <namhyung.kim@lge.com>

Separate out the default behavior to "live" subcommand. It's a
preparation to support more subcommands like "record" and "report".

Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
---
tools/perf/builtin-ftrace.c | 133 ++++++++++++++++++++++++++------------------
1 file changed, 80 insertions(+), 53 deletions(-)

diff --git a/tools/perf/builtin-ftrace.c b/tools/perf/builtin-ftrace.c
index 642aa49c66d7..1bb6d1ff0eb1 100644
--- a/tools/perf/builtin-ftrace.c
+++ b/tools/perf/builtin-ftrace.c
@@ -171,19 +171,13 @@ static int reset_tracing_cpu(void)
return 0;
}

-static int __cmd_ftrace(struct perf_ftrace *ftrace, int argc, const char **argv)
+static int do_ftrace_live(struct perf_ftrace *ftrace)
{
char *trace_file;
int trace_fd;
char buf[4096];
- struct pollfd pollfd = {
- .events = POLLIN,
- };
-
- if (geteuid() != 0) {
- pr_err("ftrace only works for root!\n");
- return -1;
- }
+ /* sleep 1ms if no data read */
+ struct timespec req = { .tv_nsec = 1000000 };

signal(SIGINT, sig_handler);
signal(SIGUSR1, sig_handler);
@@ -196,12 +190,6 @@ static int __cmd_ftrace(struct perf_ftrace *ftrace, int argc, const char **argv)
if (write_tracing_file("trace", "0") < 0)
goto out;

- if (argc && perf_evlist__prepare_workload(ftrace->evlist,
- &ftrace->target,
- argv, false, true) < 0) {
- goto out;
- }
-
if (set_tracing_pid(ftrace) < 0) {
pr_err("failed to set ftrace pid\n");
goto out_reset;
@@ -233,7 +221,6 @@ static int __cmd_ftrace(struct perf_ftrace *ftrace, int argc, const char **argv)
}

fcntl(trace_fd, F_SETFL, O_NONBLOCK);
- pollfd.fd = trace_fd;

if (write_tracing_file("tracing_on", "1") < 0) {
pr_err("can't enable tracing\n");
@@ -243,16 +230,18 @@ static int __cmd_ftrace(struct perf_ftrace *ftrace, int argc, const char **argv)
perf_evlist__start_workload(ftrace->evlist);

while (!done) {
- if (poll(&pollfd, 1, -1) < 0)
- break;
+ int n = read(trace_fd, buf, sizeof(buf));

- if (pollfd.revents & POLLIN) {
- int n = read(trace_fd, buf, sizeof(buf));
- if (n < 0)
- break;
- if (fwrite(buf, n, 1, stdout) != 1)
+ if (n < 0) {
+ if (errno == EINTR || errno == EAGAIN)
+ goto sleep;
+ else
break;
- }
+ } else if (n == 0) {
+sleep:
+ clock_nanosleep(CLOCK_MONOTONIC, 0, &req, NULL);
+ } else if (fwrite(buf, n, 1, stdout) != 1)
+ break;
}

write_tracing_file("tracing_on", "0");
@@ -274,61 +263,99 @@ out:
return done ? 0 : -1;
}

-int cmd_ftrace(int argc, const char **argv, const char *prefix __maybe_unused)
+static int
+__cmd_ftrace_live(struct perf_ftrace *ftrace, int argc, const char **argv)
{
- int ret;
- struct perf_ftrace ftrace = {
- .target = { .uid = UINT_MAX, },
- };
- const char * const ftrace_usage[] = {
- "perf ftrace [<options>] [<command>]",
- "perf ftrace [<options>] -- <command> [<options>]",
+ int ret = -1;
+ const char * const live_usage[] = {
+ "perf ftrace live [<options>] [<command>]",
+ "perf ftrace live [<options>] -- <command> [<options>]",
NULL
};
- const struct option ftrace_options[] = {
- OPT_STRING('t', "tracer", &ftrace.tracer, "tracer",
+ const struct option live_options[] = {
+ OPT_STRING('t', "tracer", &ftrace->tracer, "tracer",
"tracer to use: function_graph or function"),
- OPT_STRING('p', "pid", &ftrace.target.pid, "pid",
+ OPT_STRING('p', "pid", &ftrace->target.pid, "pid",
"trace on existing process id"),
OPT_INCR('v', "verbose", &verbose,
"be more verbose"),
- OPT_BOOLEAN('a', "all-cpus", &ftrace.target.system_wide,
+ OPT_BOOLEAN('a', "all-cpus", &ftrace->target.system_wide,
"system-wide collection from all CPUs"),
- OPT_STRING('C', "cpu", &ftrace.target.cpu_list, "cpu",
+ OPT_STRING('C', "cpu", &ftrace->target.cpu_list, "cpu",
"list of cpus to monitor"),
OPT_END()
};

- argc = parse_options(argc, argv, ftrace_options, ftrace_usage,
- PARSE_OPT_STOP_AT_NON_OPTION);
- if (!argc && perf_target__none(&ftrace.target))
- usage_with_options(ftrace_usage, ftrace_options);
+ argc = parse_options(argc, argv, live_options, live_usage,
+ PARSE_OPT_STOP_AT_NON_OPTION);
+ if (!argc && perf_target__none(&ftrace->target))
+ usage_with_options(live_usage, live_options);

- ret = perf_target__validate(&ftrace.target);
+ ret = perf_target__validate(&ftrace->target);
if (ret) {
char errbuf[512];

- perf_target__strerror(&ftrace.target, ret, errbuf, 512);
+ perf_target__strerror(&ftrace->target, ret, errbuf, 512);
pr_err("%s\n", errbuf);
return -EINVAL;
}

- ftrace.evlist = perf_evlist__new();
- if (ftrace.evlist == NULL)
+ ftrace->evlist = perf_evlist__new();
+ if (ftrace->evlist == NULL)
return -ENOMEM;

- ret = perf_evlist__create_maps(ftrace.evlist, &ftrace.target);
+ ret = perf_evlist__create_maps(ftrace->evlist, &ftrace->target);
if (ret < 0)
- goto out_delete_evlist;
+ goto out;
+
+ if (ftrace->tracer == NULL)
+ ftrace->tracer = DEFAULT_TRACER;
+
+ if (argc && perf_evlist__prepare_workload(ftrace->evlist,
+ &ftrace->target,
+ argv, false, true) < 0)
+ goto out_maps;
+
+ ret = do_ftrace_live(ftrace);
+
+out_maps:
+ perf_evlist__delete_maps(ftrace->evlist);
+out:
+ perf_evlist__delete(ftrace->evlist);
+
+ return ret;
+}
+
+int cmd_ftrace(int argc, const char **argv, const char *prefix __maybe_unused)
+{
+ int ret;
+ struct perf_ftrace ftrace = {
+ .target = { .uid = UINT_MAX, },
+ };
+ const char * const ftrace_usage[] = {
+ "perf ftrace {live} [<options>] [<command>]",
+ "perf ftrace {live} [<options>] -- <command> [<options>]",
+ NULL
+ };
+ const struct option ftrace_options[] = {
+ OPT_END()
+ };

- if (ftrace.tracer == NULL)
- ftrace.tracer = DEFAULT_TRACER;
+ argc = parse_options(argc, argv, ftrace_options, ftrace_usage,
+ PARSE_OPT_STOP_AT_NON_OPTION);
+ if (!argc)
+ usage_with_options(ftrace_usage, ftrace_options);

- ret = __cmd_ftrace(&ftrace, argc, argv);
+ if (geteuid() != 0) {
+ pr_err("ftrace only works for root!\n");
+ return -1;
+ }

- perf_evlist__delete_maps(ftrace.evlist);
-out_delete_evlist:
- perf_evlist__delete(ftrace.evlist);
+ if (strcmp(argv[0], "live") == 0) {
+ ret = __cmd_ftrace_live(&ftrace, argc, argv);
+ } else {
+ usage_with_options(ftrace_usage, ftrace_options);
+ }

return ret;
}
--
1.7.11.7


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