perf trace: Allow specifying which syscalls to trace

Similar to -e in strace, i.e. a comma separated list of syscall names
to trace.

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-5zku7q5wug3103k1dzn3yy63@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 46 insertions, 6 deletions

diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
index da7ae01c8394..120fdfb3d920 100644
--- a/tools/perf/builtin-trace.c
+++ b/tools/perf/builtin-trace.c
@@ -5,6 +5,7 @@
 #include "util/machine.h"
 #include "util/thread.h"
 #include "util/parse-options.h"
+#include "util/strlist.h"
 #include "util/thread_map.h"
 
 #include <libaudit.h>
@@ -47,6 +48,7 @@ static struct syscall_fmt *syscall_fmt__find(const char *name)
 struct syscall {
         struct event_format *tp_format;
         const char          *name;
+        bool                filtered;
         struct syscall_fmt  *fmt;
 };
 
@@ -110,6 +112,7 @@ struct trace {
         struct perf_record_opts opts;
         struct machine          host;
         u64                     base_time;
+        struct strlist          *ev_qualifier;
         unsigned long           nr_events;
         bool                    sched;
         bool                    multiple_threads;
@@ -226,6 +229,16 @@ static int trace__read_syscall_info(struct trace *trace, int id)
 
         sc = trace->syscalls.table + id;
         sc->name = name;
+
+        if (trace->ev_qualifier && !strlist__find(trace->ev_qualifier, name)) {
+                sc->filtered = true;
+                /*
+                 * No need to do read tracepoint information since this will be
+                 * filtered out.
+                 */
+                return 0;
+        }
+
         sc->fmt  = syscall_fmt__find(sc->name);
 
         snprintf(tp_name, sizeof(tp_name), "sys_enter_%s", sc->name);
@@ -302,11 +315,19 @@ static int trace__sys_enter(struct trace *trace, struct perf_evsel *evsel,
         char *msg;
         void *args;
         size_t printed = 0;
-        struct thread *thread = machine__findnew_thread(&trace->host, sample->tid);
+        struct thread *thread;
         struct syscall *sc = trace__syscall_info(trace, evsel, sample);
-        struct thread_trace *ttrace = thread__trace(thread);
+        struct thread_trace *ttrace;
+
+        if (sc == NULL)
+                return -1;
 
-        if (ttrace == NULL || sc == NULL)
+        if (sc->filtered)
+                return 0;
+
+        thread = machine__findnew_thread(&trace->host, sample->tid);
+        ttrace = thread__trace(thread);
+        if (ttrace == NULL)
                 return -1;
 
         args = perf_evsel__rawptr(evsel, sample, "args");
@@ -345,11 +366,19 @@ static int trace__sys_exit(struct trace *trace, struct perf_evsel *evsel,
 {
         int ret;
         u64 duration = 0;
-        struct thread *thread = machine__findnew_thread(&trace->host, sample->tid);
-        struct thread_trace *ttrace = thread__trace(thread);
+        struct thread *thread;
         struct syscall *sc = trace__syscall_info(trace, evsel, sample);
+        struct thread_trace *ttrace;
+
+        if (sc == NULL)
+                return -1;
 
-        if (ttrace == NULL || sc == NULL)
+        if (sc->filtered)
+                return 0;
+
+        thread = machine__findnew_thread(&trace->host, sample->tid);
+        ttrace = thread__trace(thread);
+        if (ttrace == NULL)
                 return -1;
 
         ret = perf_evsel__intval(evsel, sample, "ret");
@@ -634,7 +663,10 @@ int cmd_trace(int argc, const char **argv, const char *prefix __maybe_unused)
                         .mmap_pages    = 1024,
                 },
         };
+        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('p', "pid", &trace.opts.target.pid, "pid",
                     "trace events on existing process id"),
         OPT_STRING(0, "tid", &trace.opts.target.tid, "tid",
@@ -660,6 +692,14 @@ int cmd_trace(int argc, const char **argv, const char *prefix __maybe_unused)
 
         argc = parse_options(argc, argv, trace_options, trace_usage, 0);
 
+        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;
+                }
+        }
+
         err = perf_target__validate(&trace.opts.target);
         if (err) {
                 perf_target__strerror(&trace.opts.target, err, bf, sizeof(bf));