perf trace: Use vfs_getname hook if available
Initially it tries to find a probe:vfs_getname that should be setup
with:
perf probe 'vfs_getname=getname_flags:65 pathname=result->name:string'
or with slight changes to cope with code flux in the getname_flags code.
In the future, if a "vfs:getname" tracepoint becomes available, then it
will be preferred.
This is not strictly required and more expensive method of reading the
/proc/pid/fd/ symlink will be used when the fd->path array entry is not
populated by a previous vfs_getname + open syscall ret sequence.
As with any other 'perf probe' probe the setup must be done just once
and the probe will be left inactive, waiting for users, be it 'perf
trace' of any other tool.
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.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-ujg8se8glq5izmu8cdkq15po@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
index 763bef4..86d2b1f 100644
--- a/tools/perf/builtin-trace.c
+++ b/tools/perf/builtin-trace.c
@@ -951,7 +951,10 @@
struct trace {
struct perf_tool tool;
- int audit_machine;
+ struct {
+ int machine;
+ int open_id;
+ } audit;
struct {
int max;
struct syscall *table;
@@ -965,14 +968,19 @@
struct strlist *ev_qualifier;
bool not_ev_qualifier;
bool live;
+ const char *last_vfs_getname;
struct intlist *tid_list;
struct intlist *pid_list;
bool sched;
bool multiple_threads;
bool summary;
bool show_comm;
+ bool show_tool_stats;
double duration_filter;
double runtime_ms;
+ struct {
+ u64 vfs_getname, proc_getname;
+ } stats;
};
static int trace__set_fd_pathname(struct thread *thread, int fd, const char *pathname)
@@ -1027,7 +1035,8 @@
return trace__set_fd_pathname(thread, fd, pathname);
}
-static const char *thread__fd_path(struct thread *thread, int fd, bool live)
+static const char *thread__fd_path(struct thread *thread, int fd,
+ struct trace *trace)
{
struct thread_trace *ttrace = thread->priv;
@@ -1037,9 +1046,13 @@
if (fd < 0)
return NULL;
- if ((fd > ttrace->paths.max || ttrace->paths.table[fd] == NULL) &&
- (!live || thread__read_fd_path(thread, fd)))
- return 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)) {
+ return NULL;
+ }
return ttrace->paths.table[fd];
}
@@ -1049,7 +1062,7 @@
{
int fd = arg->val;
size_t printed = scnprintf(bf, size, "%d", fd);
- const char *path = thread__fd_path(arg->thread, fd, arg->trace->live);
+ const char *path = thread__fd_path(arg->thread, fd, arg->trace);
if (path)
printed += scnprintf(bf + printed, size - printed, "<%s>", path);
@@ -1186,7 +1199,7 @@
{
char tp_name[128];
struct syscall *sc;
- const char *name = audit_syscall_to_name(id, trace->audit_machine);
+ const char *name = audit_syscall_to_name(id, trace->audit.machine);
if (name == NULL)
return -1;
@@ -1450,6 +1463,12 @@
ret = perf_evsel__intval(evsel, sample, "ret");
+ if (id == trace->audit.open_id && ret >= 0 && trace->last_vfs_getname) {
+ trace__set_fd_pathname(thread, ret, trace->last_vfs_getname);
+ trace->last_vfs_getname = NULL;
+ ++trace->stats.vfs_getname;
+ }
+
ttrace = thread->priv;
ttrace->exit_time = sample->time;
@@ -1494,6 +1513,13 @@
return 0;
}
+static int trace__vfs_getname(struct trace *trace, struct perf_evsel *evsel,
+ struct perf_sample *sample)
+{
+ trace->last_vfs_getname = perf_evsel__rawptr(evsel, sample, "pathname");
+ return 0;
+}
+
static int trace__sched_stat_runtime(struct trace *trace, struct perf_evsel *evsel,
struct perf_sample *sample)
{
@@ -1616,6 +1642,22 @@
static size_t trace__fprintf_thread_summary(struct trace *trace, FILE *fp);
+static void perf_evlist__add_vfs_getname(struct perf_evlist *evlist)
+{
+ struct perf_evsel *evsel = perf_evsel__newtp("probe", "vfs_getname",
+ evlist->nr_entries);
+ if (evsel == NULL)
+ return;
+
+ if (perf_evsel__field(evsel, "pathname") == NULL) {
+ perf_evsel__delete(evsel);
+ return;
+ }
+
+ evsel->handler.func = trace__vfs_getname;
+ perf_evlist__add(evlist, evsel);
+}
+
static int trace__run(struct trace *trace, int argc, const char **argv)
{
struct perf_evlist *evlist = perf_evlist__new();
@@ -1635,6 +1677,8 @@
perf_evlist__add_newtp(evlist, "raw_syscalls", "sys_exit", trace__sys_exit))
goto out_error_tp;
+ perf_evlist__add_vfs_getname(evlist);
+
if (trace->sched &&
perf_evlist__add_newtp(evlist, "sched", "sched_stat_runtime",
trace__sched_stat_runtime))
@@ -1741,12 +1785,22 @@
if (done)
perf_evlist__disable(evlist);
-
- goto again;
+ else
+ goto again;
out_unmap_evlist:
- if (!err && trace->summary)
- trace__fprintf_thread_summary(trace, trace->output);
+ if (!err) {
+ if (trace->summary)
+ trace__fprintf_thread_summary(trace, trace->output);
+
+ if (trace->show_tool_stats) {
+ fprintf(trace->output, "Stats:\n "
+ " vfs_getname : %" PRIu64 "\n"
+ " proc_getname: %" PRIu64 "\n",
+ trace->stats.vfs_getname,
+ trace->stats.proc_getname);
+ }
+ }
perf_evlist__munmap(evlist);
out_close_evlist:
@@ -1788,6 +1842,7 @@
const struct perf_evsel_str_handler handlers[] = {
{ "raw_syscalls:sys_enter", trace__sys_enter, },
{ "raw_syscalls:sys_exit", trace__sys_exit, },
+ { "probe:vfs_getname", trace__vfs_getname, },
};
struct perf_session *session;
@@ -1997,7 +2052,10 @@
NULL
};
struct trace trace = {
- .audit_machine = audit_detect_machine(),
+ .audit = {
+ .machine = audit_detect_machine(),
+ .open_id = audit_name_to_syscall("open", trace.audit.machine),
+ },
.syscalls = {
. max = -1,
},
@@ -2019,6 +2077,7 @@
const struct option trace_options[] = {
OPT_BOOLEAN(0, "comm", &trace.show_comm,
"show the thread COMM next to its id"),
+ OPT_BOOLEAN(0, "tool_stats", &trace.show_tool_stats, "show tool stats"),
OPT_STRING('e', "expr", &ev_qualifier_str, "expr",
"list of events to trace"),
OPT_STRING('o', "output", &output_name, "file", "output file name"),