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authorLinus Torvalds <torvalds@linux-foundation.org>2014-08-04 16:09:53 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2014-08-04 16:09:53 -0700
commitef35ad26f8ff44d2c93e29952cdb336bda729d9d (patch)
treee2921072b9f4d820b18d6e5bc489b64ef2068668 /tools/perf/builtin-trace.c
parent8efb90cf1e80129fad197b916714e1d01ee183d2 (diff)
parentf9b9f812235d53f774a083e88a5a23b517a69752 (diff)
Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull perf changes from Ingo Molnar: "Kernel side changes: - Consolidate the PMU interrupt-disabled code amongst architectures (Vince Weaver) - misc fixes Tooling changes (new features, user visible changes): - Add support for pagefault tracing in 'trace', please see multiple examples in the changeset messages (Stanislav Fomichev). - Add pagefault statistics in 'trace' (Stanislav Fomichev) - Add header for columns in 'top' and 'report' TUI browsers (Jiri Olsa) - Add pagefault statistics in 'trace' (Stanislav Fomichev) - Add IO mode into timechart command (Stanislav Fomichev) - Fallback to syscalls:* when raw_syscalls:* is not available in the perl and python perf scripts. (Daniel Bristot de Oliveira) - Add --repeat global option to 'perf bench' to be used in benchmarks such as the existing 'futex' one, that was modified to use it instead of a local option. (Davidlohr Bueso) - Fix fd -> pathname resolution in 'trace', be it using /proc or a vfs_getname probe point. (Arnaldo Carvalho de Melo) - Add suggestion of how to set perf_event_paranoid sysctl, to help non-root users trying tools like 'trace' to get a working environment. (Arnaldo Carvalho de Melo) - Updates from trace-cmd for traceevent plugin_kvm plus args cleanup (Steven Rostedt, Jan Kiszka) - Support S/390 in 'perf kvm stat' (Alexander Yarygin) Tooling infrastructure changes: - Allow reserving a row for header purposes in the hists browser (Arnaldo Carvalho de Melo) - Various fixes and prep work related to supporting Intel PT (Adrian Hunter) - Introduce multiple debug variables control (Jiri Olsa) - Add callchain and additional sample information for python scripts (Joseph Schuchart) - More prep work to support Intel PT: (Adrian Hunter) - Polishing 'script' BTS output - 'inject' can specify --kallsym - VDSO is per machine, not a global var - Expose data addr lookup functions previously private to 'script' - Large mmap fixes in events processing - Include standard stringify macros in power pc code (Sukadev Bhattiprolu) Tooling cleanups: - Convert open coded equivalents to asprintf() (Andy Shevchenko) - Remove needless reassignments in 'trace' (Arnaldo Carvalho de Melo) - Cache the is_exit syscall test in 'trace) (Arnaldo Carvalho de Melo) - No need to reimplement err() in 'perf bench sched-messaging', drop barf(). (Davidlohr Bueso). - Remove ev_name argument from perf_evsel__hists_browse, can be obtained from the other parameters. (Jiri Olsa) Tooling fixes: - Fix memory leak in the 'sched-messaging' perf bench test. (Davidlohr Bueso) - The -o and -n 'perf bench mem' options are mutually exclusive, emit error when both are specified. (Davidlohr Bueso) - Fix scrollbar refresh row index in the ui browser, problem exposed now that headers will be added and will be allowed to be switched on/off. (Jiri Olsa) - Handle the num array type in python properly (Sebastian Andrzej Siewior) - Fix wrong condition for allocation failure (Jiri Olsa) - Adjust callchain based on DWARF debug info on powerpc (Sukadev Bhattiprolu) - Fix a risk for doing free on uninitialized pointer in traceevent lib (Rickard Strandqvist) - Update attr test with PERF_FLAG_FD_CLOEXEC flag (Jiri Olsa) - Enable close-on-exec flag on perf file descriptor (Yann Droneaud) - Fix build on gcc 4.4.7 (Arnaldo Carvalho de Melo) - Event ordering fixes (Jiri Olsa)" * 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (123 commits) Revert "perf tools: Fix jump label always changing during tracing" perf tools: Fix perf usage string leftover perf: Check permission only for parent tracepoint event perf record: Store PERF_RECORD_FINISHED_ROUND only for nonempty rounds perf record: Always force PERF_RECORD_FINISHED_ROUND event perf inject: Add --kallsyms parameter perf tools: Expose 'addr' functions so they can be reused perf session: Fix accounting of ordered samples queue perf powerpc: Include util/util.h and remove stringify macros perf tools: Fix build on gcc 4.4.7 perf tools: Add thread parameter to vdso__dso_findnew() perf tools: Add dso__type() perf tools: Separate the VDSO map name from the VDSO dso name perf tools: Add vdso__new() perf machine: Fix the lifetime of the VDSO temporary file perf tools: Group VDSO global variables into a structure perf session: Add ability to skip 4GiB or more perf session: Add ability to 'skip' a non-piped event stream perf tools: Pass machine to vdso__dso_findnew() perf tools: Add dso__data_size() ...
Diffstat (limited to 'tools/perf/builtin-trace.c')
-rw-r--r--tools/perf/builtin-trace.c266
1 files changed, 222 insertions, 44 deletions
diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
index f954c26de231..a6c375224f46 100644
--- a/tools/perf/builtin-trace.c
+++ b/tools/perf/builtin-trace.c
@@ -1108,6 +1108,7 @@ struct syscall {
struct event_format *tp_format;
const char *name;
bool filtered;
+ bool is_exit;
struct syscall_fmt *fmt;
size_t (**arg_scnprintf)(char *bf, size_t size, struct syscall_arg *arg);
void **arg_parm;
@@ -1132,6 +1133,7 @@ struct thread_trace {
u64 exit_time;
bool entry_pending;
unsigned long nr_events;
+ unsigned long pfmaj, pfmin;
char *entry_str;
double runtime_ms;
struct {
@@ -1177,6 +1179,9 @@ fail:
return NULL;
}
+#define TRACE_PFMAJ (1 << 0)
+#define TRACE_PFMIN (1 << 1)
+
struct trace {
struct perf_tool tool;
struct {
@@ -1211,6 +1216,8 @@ struct trace {
bool summary_only;
bool show_comm;
bool show_tool_stats;
+ bool trace_syscalls;
+ int trace_pgfaults;
};
static int trace__set_fd_pathname(struct thread *thread, int fd, const char *pathname)
@@ -1276,11 +1283,11 @@ static const char *thread__fd_path(struct thread *thread, int fd,
if (fd < 0)
return NULL;
- if ((fd > ttrace->paths.max || ttrace->paths.table[fd] == NULL))
+ if ((fd > ttrace->paths.max || ttrace->paths.table[fd] == NULL)) {
if (!trace->live)
return NULL;
++trace->stats.proc_getname;
- if (thread__read_fd_path(thread, fd)) {
+ if (thread__read_fd_path(thread, fd))
return NULL;
}
@@ -1473,6 +1480,8 @@ static int trace__read_syscall_info(struct trace *trace, int id)
if (sc->tp_format == NULL)
return -1;
+ sc->is_exit = !strcmp(name, "exit_group") || !strcmp(name, "exit");
+
return syscall__set_arg_fmts(sc);
}
@@ -1535,6 +1544,7 @@ static size_t syscall__scnprintf_args(struct syscall *sc, char *bf, size_t size,
}
typedef int (*tracepoint_handler)(struct trace *trace, struct perf_evsel *evsel,
+ union perf_event *event,
struct perf_sample *sample);
static struct syscall *trace__syscall_info(struct trace *trace,
@@ -1607,6 +1617,7 @@ static void thread__update_stats(struct thread_trace *ttrace,
}
static int trace__sys_enter(struct trace *trace, struct perf_evsel *evsel,
+ union perf_event *event __maybe_unused,
struct perf_sample *sample)
{
char *msg;
@@ -1629,7 +1640,6 @@ static int trace__sys_enter(struct trace *trace, struct perf_evsel *evsel,
return -1;
args = perf_evsel__sc_tp_ptr(evsel, args, sample);
- ttrace = thread->priv;
if (ttrace->entry_str == NULL) {
ttrace->entry_str = malloc(1024);
@@ -1644,7 +1654,7 @@ static int trace__sys_enter(struct trace *trace, struct perf_evsel *evsel,
printed += syscall__scnprintf_args(sc, msg + printed, 1024 - printed,
args, trace, thread);
- if (!strcmp(sc->name, "exit_group") || !strcmp(sc->name, "exit")) {
+ if (sc->is_exit) {
if (!trace->duration_filter && !trace->summary_only) {
trace__fprintf_entry_head(trace, thread, 1, sample->time, trace->output);
fprintf(trace->output, "%-70s\n", ttrace->entry_str);
@@ -1656,6 +1666,7 @@ static int trace__sys_enter(struct trace *trace, struct perf_evsel *evsel,
}
static int trace__sys_exit(struct trace *trace, struct perf_evsel *evsel,
+ union perf_event *event __maybe_unused,
struct perf_sample *sample)
{
int ret;
@@ -1687,8 +1698,6 @@ static int trace__sys_exit(struct trace *trace, struct perf_evsel *evsel,
++trace->stats.vfs_getname;
}
- ttrace = thread->priv;
-
ttrace->exit_time = sample->time;
if (ttrace->entry_time) {
@@ -1735,6 +1744,7 @@ out:
}
static int trace__vfs_getname(struct trace *trace, struct perf_evsel *evsel,
+ union perf_event *event __maybe_unused,
struct perf_sample *sample)
{
trace->last_vfs_getname = perf_evsel__rawptr(evsel, sample, "pathname");
@@ -1742,6 +1752,7 @@ static int trace__vfs_getname(struct trace *trace, struct perf_evsel *evsel,
}
static int trace__sched_stat_runtime(struct trace *trace, struct perf_evsel *evsel,
+ union perf_event *event __maybe_unused,
struct perf_sample *sample)
{
u64 runtime = perf_evsel__intval(evsel, sample, "runtime");
@@ -1768,6 +1779,80 @@ out_dump:
return 0;
}
+static void print_location(FILE *f, struct perf_sample *sample,
+ struct addr_location *al,
+ bool print_dso, bool print_sym)
+{
+
+ if ((verbose || print_dso) && al->map)
+ fprintf(f, "%s@", al->map->dso->long_name);
+
+ if ((verbose || print_sym) && al->sym)
+ fprintf(f, "%s+0x%" PRIx64, al->sym->name,
+ al->addr - al->sym->start);
+ else if (al->map)
+ fprintf(f, "0x%" PRIx64, al->addr);
+ else
+ fprintf(f, "0x%" PRIx64, sample->addr);
+}
+
+static int trace__pgfault(struct trace *trace,
+ struct perf_evsel *evsel,
+ union perf_event *event,
+ struct perf_sample *sample)
+{
+ struct thread *thread;
+ u8 cpumode = event->header.misc & PERF_RECORD_MISC_CPUMODE_MASK;
+ struct addr_location al;
+ char map_type = 'd';
+ struct thread_trace *ttrace;
+
+ thread = machine__findnew_thread(trace->host, sample->pid, sample->tid);
+ ttrace = thread__trace(thread, trace->output);
+ if (ttrace == NULL)
+ return -1;
+
+ if (evsel->attr.config == PERF_COUNT_SW_PAGE_FAULTS_MAJ)
+ ttrace->pfmaj++;
+ else
+ ttrace->pfmin++;
+
+ if (trace->summary_only)
+ return 0;
+
+ thread__find_addr_location(thread, trace->host, cpumode, MAP__FUNCTION,
+ sample->ip, &al);
+
+ trace__fprintf_entry_head(trace, thread, 0, sample->time, trace->output);
+
+ fprintf(trace->output, "%sfault [",
+ evsel->attr.config == PERF_COUNT_SW_PAGE_FAULTS_MAJ ?
+ "maj" : "min");
+
+ print_location(trace->output, sample, &al, false, true);
+
+ fprintf(trace->output, "] => ");
+
+ thread__find_addr_location(thread, trace->host, cpumode, MAP__VARIABLE,
+ sample->addr, &al);
+
+ if (!al.map) {
+ thread__find_addr_location(thread, trace->host, cpumode,
+ MAP__FUNCTION, sample->addr, &al);
+
+ if (al.map)
+ map_type = 'x';
+ else
+ map_type = '?';
+ }
+
+ print_location(trace->output, sample, &al, true, false);
+
+ fprintf(trace->output, " (%c%c)\n", map_type, al.level);
+
+ return 0;
+}
+
static bool skip_sample(struct trace *trace, struct perf_sample *sample)
{
if ((trace->pid_list && intlist__find(trace->pid_list, sample->pid)) ||
@@ -1781,7 +1866,7 @@ static bool skip_sample(struct trace *trace, struct perf_sample *sample)
}
static int trace__process_sample(struct perf_tool *tool,
- union perf_event *event __maybe_unused,
+ union perf_event *event,
struct perf_sample *sample,
struct perf_evsel *evsel,
struct machine *machine __maybe_unused)
@@ -1799,7 +1884,7 @@ static int trace__process_sample(struct perf_tool *tool,
if (handler) {
++trace->nr_events;
- handler(trace, evsel, sample);
+ handler(trace, evsel, event, sample);
}
return err;
@@ -1826,7 +1911,7 @@ static int parse_target_str(struct trace *trace)
return 0;
}
-static int trace__record(int argc, const char **argv)
+static int trace__record(struct trace *trace, int argc, const char **argv)
{
unsigned int rec_argc, i, j;
const char **rec_argv;
@@ -1835,34 +1920,54 @@ static int trace__record(int argc, const char **argv)
"-R",
"-m", "1024",
"-c", "1",
- "-e",
};
+ const char * const sc_args[] = { "-e", };
+ unsigned int sc_args_nr = ARRAY_SIZE(sc_args);
+ const char * const majpf_args[] = { "-e", "major-faults" };
+ unsigned int majpf_args_nr = ARRAY_SIZE(majpf_args);
+ const char * const minpf_args[] = { "-e", "minor-faults" };
+ unsigned int minpf_args_nr = ARRAY_SIZE(minpf_args);
+
/* +1 is for the event string below */
- rec_argc = ARRAY_SIZE(record_args) + 1 + argc;
+ rec_argc = ARRAY_SIZE(record_args) + sc_args_nr + 1 +
+ majpf_args_nr + minpf_args_nr + argc;
rec_argv = calloc(rec_argc + 1, sizeof(char *));
if (rec_argv == NULL)
return -ENOMEM;
+ j = 0;
for (i = 0; i < ARRAY_SIZE(record_args); i++)
- rec_argv[i] = record_args[i];
-
- /* event string may be different for older kernels - e.g., RHEL6 */
- if (is_valid_tracepoint("raw_syscalls:sys_enter"))
- rec_argv[i] = "raw_syscalls:sys_enter,raw_syscalls:sys_exit";
- else if (is_valid_tracepoint("syscalls:sys_enter"))
- rec_argv[i] = "syscalls:sys_enter,syscalls:sys_exit";
- else {
- pr_err("Neither raw_syscalls nor syscalls events exist.\n");
- return -1;
+ rec_argv[j++] = record_args[i];
+
+ if (trace->trace_syscalls) {
+ for (i = 0; i < sc_args_nr; i++)
+ rec_argv[j++] = sc_args[i];
+
+ /* event string may be different for older kernels - e.g., RHEL6 */
+ if (is_valid_tracepoint("raw_syscalls:sys_enter"))
+ rec_argv[j++] = "raw_syscalls:sys_enter,raw_syscalls:sys_exit";
+ else if (is_valid_tracepoint("syscalls:sys_enter"))
+ rec_argv[j++] = "syscalls:sys_enter,syscalls:sys_exit";
+ else {
+ pr_err("Neither raw_syscalls nor syscalls events exist.\n");
+ return -1;
+ }
}
- i++;
- for (j = 0; j < (unsigned int)argc; j++, i++)
- rec_argv[i] = argv[j];
+ if (trace->trace_pgfaults & TRACE_PFMAJ)
+ for (i = 0; i < majpf_args_nr; i++)
+ rec_argv[j++] = majpf_args[i];
+
+ if (trace->trace_pgfaults & TRACE_PFMIN)
+ for (i = 0; i < minpf_args_nr; i++)
+ rec_argv[j++] = minpf_args[i];
+
+ for (i = 0; i < (unsigned int)argc; i++)
+ rec_argv[j++] = argv[i];
- return cmd_record(i, rec_argv, NULL);
+ return cmd_record(j, rec_argv, NULL);
}
static size_t trace__fprintf_thread_summary(struct trace *trace, FILE *fp);
@@ -1882,6 +1987,30 @@ static void perf_evlist__add_vfs_getname(struct perf_evlist *evlist)
perf_evlist__add(evlist, evsel);
}
+static int perf_evlist__add_pgfault(struct perf_evlist *evlist,
+ u64 config)
+{
+ struct perf_evsel *evsel;
+ struct perf_event_attr attr = {
+ .type = PERF_TYPE_SOFTWARE,
+ .mmap_data = 1,
+ };
+
+ attr.config = config;
+ attr.sample_period = 1;
+
+ event_attr_init(&attr);
+
+ evsel = perf_evsel__new(&attr);
+ if (!evsel)
+ return -ENOMEM;
+
+ evsel->handler = trace__pgfault;
+ perf_evlist__add(evlist, evsel);
+
+ return 0;
+}
+
static int trace__run(struct trace *trace, int argc, const char **argv)
{
struct perf_evlist *evlist = perf_evlist__new();
@@ -1897,10 +2026,21 @@ static int trace__run(struct trace *trace, int argc, const char **argv)
goto out;
}
- if (perf_evlist__add_syscall_newtp(evlist, trace__sys_enter, trace__sys_exit))
+ if (trace->trace_syscalls &&
+ perf_evlist__add_syscall_newtp(evlist, trace__sys_enter,
+ trace__sys_exit))
goto out_error_tp;
- perf_evlist__add_vfs_getname(evlist);
+ if (trace->trace_syscalls)
+ perf_evlist__add_vfs_getname(evlist);
+
+ if ((trace->trace_pgfaults & TRACE_PFMAJ) &&
+ perf_evlist__add_pgfault(evlist, PERF_COUNT_SW_PAGE_FAULTS_MAJ))
+ goto out_error_tp;
+
+ if ((trace->trace_pgfaults & TRACE_PFMIN) &&
+ perf_evlist__add_pgfault(evlist, PERF_COUNT_SW_PAGE_FAULTS_MIN))
+ goto out_error_tp;
if (trace->sched &&
perf_evlist__add_newtp(evlist, "sched", "sched_stat_runtime",
@@ -1982,7 +2122,8 @@ again:
goto next_event;
}
- if (sample.raw_data == NULL) {
+ if (evsel->attr.type == PERF_TYPE_TRACEPOINT &&
+ sample.raw_data == NULL) {
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);
@@ -1990,7 +2131,7 @@ again:
}
handler = evsel->handler;
- handler(trace, evsel, &sample);
+ handler(trace, evsel, event, &sample);
next_event:
perf_evlist__mmap_consume(evlist, i);
@@ -2093,13 +2234,10 @@ static int trace__replay(struct trace *trace)
if (evsel == NULL)
evsel = perf_evlist__find_tracepoint_by_name(session->evlist,
"syscalls:sys_enter");
- if (evsel == NULL) {
- pr_err("Data file does not have raw_syscalls:sys_enter event\n");
- goto out;
- }
- if (perf_evsel__init_syscall_tp(evsel, trace__sys_enter) < 0 ||
- perf_evsel__init_sc_tp_ptr_field(evsel, args)) {
+ if (evsel &&
+ (perf_evsel__init_syscall_tp(evsel, trace__sys_enter) < 0 ||
+ perf_evsel__init_sc_tp_ptr_field(evsel, args))) {
pr_err("Error during initialize raw_syscalls:sys_enter event\n");
goto out;
}
@@ -2109,15 +2247,19 @@ static int trace__replay(struct trace *trace)
if (evsel == NULL)
evsel = perf_evlist__find_tracepoint_by_name(session->evlist,
"syscalls:sys_exit");
- if (evsel == NULL) {
- pr_err("Data file does not have raw_syscalls:sys_exit event\n");
+ if (evsel &&
+ (perf_evsel__init_syscall_tp(evsel, trace__sys_exit) < 0 ||
+ perf_evsel__init_sc_tp_uint_field(evsel, ret))) {
+ pr_err("Error during initialize raw_syscalls:sys_exit event\n");
goto out;
}
- if (perf_evsel__init_syscall_tp(evsel, trace__sys_exit) < 0 ||
- perf_evsel__init_sc_tp_uint_field(evsel, ret)) {
- pr_err("Error during initialize raw_syscalls:sys_exit event\n");
- goto out;
+ evlist__for_each(session->evlist, evsel) {
+ if (evsel->attr.type == PERF_TYPE_SOFTWARE &&
+ (evsel->attr.config == PERF_COUNT_SW_PAGE_FAULTS_MAJ ||
+ evsel->attr.config == PERF_COUNT_SW_PAGE_FAULTS_MIN ||
+ evsel->attr.config == PERF_COUNT_SW_PAGE_FAULTS))
+ evsel->handler = trace__pgfault;
}
err = parse_target_str(trace);
@@ -2217,6 +2359,10 @@ static int trace__fprintf_one_thread(struct thread *thread, void *priv)
printed += fprintf(fp, " %s (%d), ", thread__comm_str(thread), thread->tid);
printed += fprintf(fp, "%lu events, ", ttrace->nr_events);
printed += fprintf(fp, "%.1f%%", ratio);
+ if (ttrace->pfmaj)
+ printed += fprintf(fp, ", %lu majfaults", ttrace->pfmaj);
+ if (ttrace->pfmin)
+ printed += fprintf(fp, ", %lu minfaults", ttrace->pfmin);
printed += fprintf(fp, ", %.3f msec\n", ttrace->runtime_ms);
printed += thread__dump_stats(ttrace, trace, fp);
@@ -2264,6 +2410,23 @@ static int trace__open_output(struct trace *trace, const char *filename)
return trace->output == NULL ? -errno : 0;
}
+static int parse_pagefaults(const struct option *opt, const char *str,
+ int unset __maybe_unused)
+{
+ int *trace_pgfaults = opt->value;
+
+ if (strcmp(str, "all") == 0)
+ *trace_pgfaults |= TRACE_PFMAJ | TRACE_PFMIN;
+ else if (strcmp(str, "maj") == 0)
+ *trace_pgfaults |= TRACE_PFMAJ;
+ else if (strcmp(str, "min") == 0)
+ *trace_pgfaults |= TRACE_PFMIN;
+ else
+ return -1;
+
+ return 0;
+}
+
int cmd_trace(int argc, const char **argv, const char *prefix __maybe_unused)
{
const char * const trace_usage[] = {
@@ -2293,6 +2456,7 @@ int cmd_trace(int argc, const char **argv, const char *prefix __maybe_unused)
},
.output = stdout,
.show_comm = true,
+ .trace_syscalls = true,
};
const char *output_name = NULL;
const char *ev_qualifier_str = NULL;
@@ -2330,20 +2494,34 @@ int cmd_trace(int argc, const char **argv, const char *prefix __maybe_unused)
"Show only syscall summary with statistics"),
OPT_BOOLEAN('S', "with-summary", &trace.summary,
"Show all syscalls and summary with statistics"),
+ OPT_CALLBACK_DEFAULT('F', "pf", &trace.trace_pgfaults, "all|maj|min",
+ "Trace pagefaults", parse_pagefaults, "maj"),
+ OPT_BOOLEAN(0, "syscalls", &trace.trace_syscalls, "Trace syscalls"),
OPT_END()
};
int err;
char bf[BUFSIZ];
- if ((argc > 1) && (strcmp(argv[1], "record") == 0))
- return trace__record(argc-2, &argv[2]);
+ argc = parse_options(argc, argv, trace_options, trace_usage,
+ PARSE_OPT_STOP_AT_NON_OPTION);
- argc = parse_options(argc, argv, trace_options, trace_usage, 0);
+ if (trace.trace_pgfaults) {
+ trace.opts.sample_address = true;
+ trace.opts.sample_time = true;
+ }
+
+ if ((argc >= 1) && (strcmp(argv[0], "record") == 0))
+ return trace__record(&trace, argc-1, &argv[1]);
/* summary_only implies summary option, but don't overwrite summary if set */
if (trace.summary_only)
trace.summary = trace.summary_only;
+ if (!trace.trace_syscalls && !trace.trace_pgfaults) {
+ pr_err("Please specify something to trace.\n");
+ return -1;
+ }
+
if (output_name != NULL) {
err = trace__open_output(&trace, output_name);
if (err < 0) {