perf trace: Implement -o/--output filename

To output all 'trace' output to a filename, just like 'strace -ofile'

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-6q1homkwoayhmoq64y5vhel6@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

2 files changed, 90 insertions, 48 deletions

diff --git a/tools/perf/Documentation/perf-trace.txt b/tools/perf/Documentation/perf-trace.txt
index 3b3552a8959e..2794efce47a1 100644
--- a/tools/perf/Documentation/perf-trace.txt
+++ b/tools/perf/Documentation/perf-trace.txt
@@ -30,6 +30,10 @@ OPTIONS
 --expr::
         List of events to show, currently only syscall names.
 
+-o::
+--output=::
+        Output file name.
+
 -p::
 --pid=::
         Record events on existing process ID (comma separated list).
diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
index 120fdfb3d920..42353165472a 100644
--- a/tools/perf/builtin-trace.c
+++ b/tools/perf/builtin-trace.c
@@ -63,7 +63,7 @@ static size_t fprintf_duration(unsigned long t, FILE *fp)
                 printed += color_fprintf(fp, PERF_COLOR_YELLOW, "%6.3f ms", duration);
         else
                 printed += color_fprintf(fp, PERF_COLOR_NORMAL, "%6.3f ms", duration);
-        return printed + fprintf(stdout, "): ");
+        return printed + fprintf(fp, "): ");
 }
 
 struct thread_trace {
@@ -80,7 +80,7 @@ static struct thread_trace *thread_trace__new(void)
         return zalloc(sizeof(struct thread_trace));
 }
 
-static struct thread_trace *thread__trace(struct thread *thread)
+static struct thread_trace *thread__trace(struct thread *thread, FILE *fp)
 {
         struct thread_trace *ttrace;
 
@@ -98,12 +98,13 @@ static struct thread_trace *thread__trace(struct thread *thread)
 
         return ttrace;
 fail:
-        color_fprintf(stdout, PERF_COLOR_RED,
+        color_fprintf(fp, PERF_COLOR_RED,
                       "WARNING: not enough memory, dropping samples!\n");
         return NULL;
 }
 
 struct trace {
+        struct perf_tool        tool;
         int                     audit_machine;
         struct {
                 int             max;
@@ -112,6 +113,7 @@ struct trace {
         struct perf_record_opts opts;
         struct machine          host;
         u64                     base_time;
+        FILE                    *output;
         struct strlist          *ev_qualifier;
         unsigned long           nr_events;
         bool                    sched;
@@ -151,13 +153,14 @@ static size_t trace__fprintf_entry_head(struct trace *trace, struct thread *thre
         return printed;
 }
 
-static int trace__process_event(struct machine *machine, union perf_event *event)
+static int trace__process_event(struct trace *trace, struct machine *machine,
+                                union perf_event *event)
 {
         int ret = 0;
 
         switch (event->header.type) {
         case PERF_RECORD_LOST:
-                color_fprintf(stdout, PERF_COLOR_RED,
+                color_fprintf(trace->output, PERF_COLOR_RED,
                               "LOST %" PRIu64 " events!\n", event->lost.lost);
                 ret = machine__process_lost_event(machine, event);
         default:
@@ -168,12 +171,13 @@ static int trace__process_event(struct machine *machine, union perf_event *event
         return ret;
 }
 
-static int trace__tool_process(struct perf_tool *tool __maybe_unused,
+static int trace__tool_process(struct perf_tool *tool,
                                union perf_event *event,
                                struct perf_sample *sample __maybe_unused,
                                struct machine *machine)
 {
-        return trace__process_event(machine, event);
+        struct trace *trace = container_of(tool, struct trace, tool);
+        return trace__process_event(trace, machine, event);
 }
 
 static int trace__symbols_init(struct trace *trace, struct perf_evlist *evlist)
@@ -187,11 +191,11 @@ static int trace__symbols_init(struct trace *trace, struct perf_evlist *evlist)
         machine__create_kernel_maps(&trace->host);
 
         if (perf_target__has_task(&trace->opts.target)) {
-                err = perf_event__synthesize_thread_map(NULL, evlist->threads,
+                err = perf_event__synthesize_thread_map(&trace->tool, evlist->threads,
                                                         trace__tool_process,
                                                         &trace->host);
         } else {
-                err = perf_event__synthesize_threads(NULL, trace__tool_process,
+                err = perf_event__synthesize_threads(&trace->tool, trace__tool_process,
                                                      &trace->host);
         }
 
@@ -288,7 +292,7 @@ static struct syscall *trace__syscall_info(struct trace *trace,
         int id = perf_evsel__intval(evsel, sample, "id");
 
         if (id < 0) {
-                printf("Invalid syscall %d id, skipping...\n", id);
+                fprintf(trace->output, "Invalid syscall %d id, skipping...\n", id);
                 return NULL;
         }
 
@@ -302,10 +306,10 @@ static struct syscall *trace__syscall_info(struct trace *trace,
         return &trace->syscalls.table[id];
 
 out_cant_read:
-        printf("Problems reading syscall %d", id);
+        fprintf(trace->output, "Problems reading syscall %d", id);
         if (id <= trace->syscalls.max && trace->syscalls.table[id].name != NULL)
-                printf("(%s)", trace->syscalls.table[id].name);
-        puts(" information");
+                fprintf(trace->output, "(%s)", trace->syscalls.table[id].name);
+        fputs(" information", trace->output);
         return NULL;
 }
 
@@ -326,13 +330,13 @@ static int trace__sys_enter(struct trace *trace, struct perf_evsel *evsel,
                 return 0;
 
         thread = machine__findnew_thread(&trace->host, sample->tid);
-        ttrace = thread__trace(thread);
+        ttrace = thread__trace(thread, trace->output);
         if (ttrace == NULL)
                 return -1;
 
         args = perf_evsel__rawptr(evsel, sample, "args");
         if (args == NULL) {
-                printf("Problems reading syscall arguments\n");
+                fprintf(trace->output, "Problems reading syscall arguments\n");
                 return -1;
         }
 
@@ -352,8 +356,8 @@ static int trace__sys_enter(struct trace *trace, struct perf_evsel *evsel,
 
         if (!strcmp(sc->name, "exit_group") || !strcmp(sc->name, "exit")) {
                 if (!trace->duration_filter) {
-                        trace__fprintf_entry_head(trace, thread, 1, sample->time, stdout);
-                        printf("%-70s\n", ttrace->entry_str);
+                        trace__fprintf_entry_head(trace, thread, 1, sample->time, trace->output);
+                        fprintf(trace->output, "%-70s\n", ttrace->entry_str);
                 }
         } else
                 ttrace->entry_pending = true;
@@ -377,7 +381,7 @@ static int trace__sys_exit(struct trace *trace, struct perf_evsel *evsel,
                 return 0;
 
         thread = machine__findnew_thread(&trace->host, sample->tid);
-        ttrace = thread__trace(thread);
+        ttrace = thread__trace(thread, trace->output);
         if (ttrace == NULL)
                 return -1;
 
@@ -394,14 +398,14 @@ static int trace__sys_exit(struct trace *trace, struct perf_evsel *evsel,
         } else if (trace->duration_filter)
                 goto out;
 
-        trace__fprintf_entry_head(trace, thread, duration, sample->time, stdout);
+        trace__fprintf_entry_head(trace, thread, duration, sample->time, trace->output);
 
         if (ttrace->entry_pending) {
-                printf("%-70s", ttrace->entry_str);
+                fprintf(trace->output, "%-70s", ttrace->entry_str);
         } else {
-                printf(" ... [");
-                color_fprintf(stdout, PERF_COLOR_YELLOW, "continued");
-                printf("]: %s()", sc->name);
+                fprintf(trace->output, " ... [");
+                color_fprintf(trace->output, PERF_COLOR_YELLOW, "continued");
+                fprintf(trace->output, "]: %s()", sc->name);
         }
 
         if (ret < 0 && sc->fmt && sc->fmt->errmsg) {
@@ -409,13 +413,13 @@ static int trace__sys_exit(struct trace *trace, struct perf_evsel *evsel,
                 const char *emsg = strerror_r(-ret, bf, sizeof(bf)),
                            *e = audit_errno_to_name(-ret);
 
-                printf(") = -1 %s %s", e, emsg);
+                fprintf(trace->output, ") = -1 %s %s", e, emsg);
         } else if (ret == 0 && sc->fmt && sc->fmt->timeout)
-                printf(") = 0 Timeout");
+                fprintf(trace->output, ") = 0 Timeout");
         else
-                printf(") = %d", ret);
+                fprintf(trace->output, ") = %d", ret);
 
-        putchar('\n');
+        fputc('\n', trace->output);
 out:
         ttrace->entry_pending = false;
 
@@ -428,7 +432,7 @@ static int trace__sched_stat_runtime(struct trace *trace, struct perf_evsel *evs
         u64 runtime = perf_evsel__intval(evsel, sample, "runtime");
         double runtime_ms = (double)runtime / NSEC_PER_MSEC;
         struct thread *thread = machine__findnew_thread(&trace->host, sample->tid);
-        struct thread_trace *ttrace = thread__trace(thread);
+        struct thread_trace *ttrace = thread__trace(thread, trace->output);
 
         if (ttrace == NULL)
                 goto out_dump;
@@ -438,7 +442,7 @@ static int trace__sched_stat_runtime(struct trace *trace, struct perf_evsel *evs
         return 0;
 
 out_dump:
-        printf("%s: comm=%s,pid=%u,runtime=%" PRIu64 ",vruntime=%" PRIu64 ")\n",
+        fprintf(trace->output, "%s: comm=%s,pid=%u,runtime=%" PRIu64 ",vruntime=%" PRIu64 ")\n",
                evsel->name,
                perf_evsel__strval(evsel, sample, "comm"),
                (pid_t)perf_evsel__intval(evsel, sample, "pid"),
@@ -456,32 +460,32 @@ static int trace__run(struct trace *trace, int argc, const char **argv)
         const bool forks = argc > 0;
 
         if (evlist == NULL) {
-                printf("Not enough memory to run!\n");
+                fprintf(trace->output, "Not enough memory to run!\n");
                 goto out;
         }
 
         if (perf_evlist__add_newtp(evlist, "raw_syscalls", "sys_enter", trace__sys_enter) ||
             perf_evlist__add_newtp(evlist, "raw_syscalls", "sys_exit", trace__sys_exit)) {
-                printf("Couldn't read the raw_syscalls tracepoints information!\n");
+                fprintf(trace->output, "Couldn't read the raw_syscalls tracepoints information!\n");
                 goto out_delete_evlist;
         }
 
         if (trace->sched &&
             perf_evlist__add_newtp(evlist, "sched", "sched_stat_runtime",
                                    trace__sched_stat_runtime)) {
-                printf("Couldn't read the sched_stat_runtime tracepoint information!\n");
+                fprintf(trace->output, "Couldn't read the sched_stat_runtime tracepoint information!\n");
                 goto out_delete_evlist;
         }
 
         err = perf_evlist__create_maps(evlist, &trace->opts.target);
         if (err < 0) {
-                printf("Problems parsing the target to trace, check your options!\n");
+                fprintf(trace->output, "Problems parsing the target to trace, check your options!\n");
                 goto out_delete_evlist;
         }
 
         err = trace__symbols_init(trace, evlist);
         if (err < 0) {
-                printf("Problems initializing symbol libraries!\n");
+                fprintf(trace->output, "Problems initializing symbol libraries!\n");
                 goto out_delete_maps;
         }
 
@@ -494,20 +498,20 @@ static int trace__run(struct trace *trace, int argc, const char **argv)
                 err = perf_evlist__prepare_workload(evlist, &trace->opts.target,
                                                     argv, false, false);
                 if (err < 0) {
-                        printf("Couldn't run the workload!\n");
+                        fprintf(trace->output, "Couldn't run the workload!\n");
                         goto out_delete_maps;
                 }
         }
 
         err = perf_evlist__open(evlist);
         if (err < 0) {
-                printf("Couldn't create the events: %s\n", strerror(errno));
+                fprintf(trace->output, "Couldn't create the events: %s\n", strerror(errno));
                 goto out_delete_maps;
         }
 
         err = perf_evlist__mmap(evlist, UINT_MAX, false);
         if (err < 0) {
-                printf("Couldn't mmap the events: %s\n", strerror(errno));
+                fprintf(trace->output, "Couldn't mmap the events: %s\n", strerror(errno));
                 goto out_close_evlist;
         }
 
@@ -532,7 +536,7 @@ again:
 
                         err = perf_evlist__parse_sample(evlist, event, &sample);
                         if (err) {
-                                printf("Can't parse sample, err = %d, skipping...\n", err);
+                                fprintf(trace->output, "Can't parse sample, err = %d, skipping...\n", err);
                                 continue;
                         }
 
@@ -540,18 +544,18 @@ again:
                                 trace->base_time = sample.time;
 
                         if (type != PERF_RECORD_SAMPLE) {
-                                trace__process_event(&trace->host, event);
+                                trace__process_event(trace, &trace->host, event);
                                 continue;
                         }
 
                         evsel = perf_evlist__id2evsel(evlist, sample.id);
                         if (evsel == NULL) {
-                                printf("Unknown tp ID %" PRIu64 ", skipping...\n", sample.id);
+                                fprintf(trace->output, "Unknown tp ID %" PRIu64 ", skipping...\n", sample.id);
                                 continue;
                         }
 
                         if (sample.raw_data == NULL) {
-                                printf("%s sample with no payload for tid: %d, cpu %d, raw_size=%d, skipping...\n",
+                                fprintf(trace->output, "%s sample with no payload for tid: %d, cpu %d, raw_size=%d, skipping...\n",
                                        perf_evsel__name(evsel), sample.tid,
                                        sample.cpu, sample.raw_size);
                                 continue;
@@ -640,6 +644,23 @@ static int trace__set_duration(const struct option *opt, const char *str,
         return 0;
 }
 
+static int trace__open_output(struct trace *trace, const char *filename)
+{
+        struct stat st;
+
+        if (!stat(filename, &st) && st.st_size) {
+                char oldname[PATH_MAX];
+
+                scnprintf(oldname, sizeof(oldname), "%s.old", filename);
+                unlink(oldname);
+                rename(filename, oldname);
+        }
+
+        trace->output = fopen(filename, "w");
+
+        return trace->output == NULL ? -errno : 0;
+}
+
 int cmd_trace(int argc, const char **argv, const char *prefix __maybe_unused)
 {
         const char * const trace_usage[] = {
@@ -662,11 +683,14 @@ int cmd_trace(int argc, const char **argv, const char *prefix __maybe_unused)
                         .no_delay      = true,
                         .mmap_pages    = 1024,
                 },
+                .output = stdout,
         };
+        const char *output_name = NULL;
         const char *ev_qualifier_str = NULL;
         const struct option trace_options[] = {
         OPT_STRING('e', "expr", &ev_qualifier_str, "expr",
                     "list of events to trace"),
+        OPT_STRING('o', "output", &output_name, "file", "output file name"),
         OPT_STRING('p', "pid", &trace.opts.target.pid, "pid",
                     "trace events on existing process id"),
         OPT_STRING(0, "tid", &trace.opts.target.tid, "tid",
@@ -692,26 +716,36 @@ int cmd_trace(int argc, const char **argv, const char *prefix __maybe_unused)
 
         argc = parse_options(argc, argv, trace_options, trace_usage, 0);
 
+        if (output_name != NULL) {
+                err = trace__open_output(&trace, output_name);
+                if (err < 0) {
+                        perror("failed to create output file");
+                        goto out;
+                }
+        }
+
         if (ev_qualifier_str != NULL) {
                 trace.ev_qualifier = strlist__new(true, ev_qualifier_str);
                 if (trace.ev_qualifier == NULL) {
-                        puts("Not enough memory to parse event qualifier");
-                        return -ENOMEM;
+                        fputs("Not enough memory to parse event qualifier",
+                              trace.output);
+                        err = -ENOMEM;
+                        goto out_close;
                 }
         }
 
         err = perf_target__validate(&trace.opts.target);
         if (err) {
                 perf_target__strerror(&trace.opts.target, err, bf, sizeof(bf));
-                printf("%s", bf);
-                return err;
+                fprintf(trace.output, "%s", bf);
+                goto out_close;
         }
 
         err = perf_target__parse_uid(&trace.opts.target);
         if (err) {
                 perf_target__strerror(&trace.opts.target, err, bf, sizeof(bf));
-                printf("%s", bf);
-                return err;
+                fprintf(trace.output, "%s", bf);
+                goto out_close;
         }
 
         if (!argc && perf_target__none(&trace.opts.target))
@@ -720,7 +754,11 @@ int cmd_trace(int argc, const char **argv, const char *prefix __maybe_unused)
         err = trace__run(&trace, argc, argv);
 
         if (trace.sched && !err)
-                trace__fprintf_thread_summary(&trace, stdout);
+                trace__fprintf_thread_summary(&trace, trace.output);
 
+out_close:
+        if (output_name != NULL)
+                fclose(trace.output);
+out:
         return err;
 }