perf trace: Beautify pid_t arguments

When reading the syscall tracepoint /format file, look for arguments
of type "pid_t" and attach the PID beautifier, that will do a lookup
on the threads it knows, i.e. the ones that came from PERF_RECORD_COMM
events and add the COMM after the pid in such args:

Excerpt of a system wide trace for syscalls with pid_t args:

  55602.977 ( 0.006 ms): bash/12122 setpgid(pid: 24347 (bash), pgid: 24347 (bash)) = 0
  55603.024 ( 0.004 ms): bash/24347 setpgid(pid: 24347 (bash), pgid: 24347 (bash)) = 0
  55691.527 (88.397 ms): bash/12122 wait4(upid: -1, stat_addr: 0x7ffe0cee1720, options: UNTRACED|CONTINUED) ...
  55692.479 ( 0.952 ms): git/24347 wait4(upid: 24368, stat_addr: 0x7ffe030d5724) ...
  55694.549 ( 2.070 ms): pre-commit/24368 wait4(upid: -1, stat_addr: 0x7ffc94f4fc10) = 24369 (pre-commit)
  55694.575 ( 0.002 ms): pre-commit/24368 wait4(upid: -1, stat_addr: 0x7ffc94f4f650, options: NOHANG) = -1 ECHILD No child processes
  55695.934 ( 0.010 ms): pre-commit/24368 wait4(upid: -1, stat_addr: 0x7ffc94f4f2d0, options: NOHANG) = 24370 (git)
  55695.937 ( 0.001 ms): pre-commit/24368 wait4(upid: -1, stat_addr: 0x7ffc94f4f2d0, options: NOHANG) = -1 ECHILD No child processes
  55717.963 ( 0.000 ms): pre-commit/24371  ... [continued]: wait4()) = 24372
  55717.978 (21.468 ms): :24371/24371 wait4(upid: -1, stat_addr: 0x7ffc94f4f230) ...
  55718.087 ( 0.109 ms): pre-commit/24371 wait4(upid: -1, stat_addr: 0x7ffc94f4f230) = 24373 (tr)
  55718.187 ( 0.096 ms): pre-commit/24371 wait4(upid: -1, stat_addr: 0x7ffc94f4f230) = 24374 (wc)
  55718.218 ( 0.002 ms): pre-commit/24371 wait4(upid: -1, stat_addr: 0x7ffc94f4eed0, options: NOHANG) = -1 ECHILD No child processes
  55718.367 ( 0.005 ms): pre-commit/24368 wait4(upid: -1, stat_addr: 0x7ffc94f4f1d0, options: NOHANG) = 24371 (pre-commit)
  55718.369 ( 0.001 ms): pre-commit/24368 wait4(upid: -1, stat_addr: 0x7ffc94f4f1d0, options: NOHANG) = -1 ECHILD No child processes
  55741.021 (49.494 ms): git/24347  ... [continued]: wait4()) = 24368 (pre-commit)
  74146.427 (18319.601 ms): git/24347 wait4(upid: 24375 (git), stat_addr: 0x7ffe030d6824) ...
  74149.036 ( 0.891 ms): bash/24391 wait4(upid: -1, stat_addr: 0x7ffe0cee0560) = 24393 (sed)

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-75yl9hzjhb020iadc81gdj8t@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/builtin-trace.c

@@ -112,6 +112,58 @@
 # define PERF_FLAG_FD_CLOEXEC		(1UL << 3) /* O_CLOEXEC */
 #endif
 
+struct trace {
+	struct perf_tool	tool;
+	struct {
+		int		machine;
+		int		open_id;
+	}			audit;
+	struct {
+		int		max;
+		struct syscall  *table;
+		struct {
+			struct perf_evsel *sys_enter,
+					  *sys_exit;
+		}		events;
+	} syscalls;
+	struct record_opts	opts;
+	struct perf_evlist	*evlist;
+	struct machine		*host;
+	struct thread		*current;
+	u64			base_time;
+	FILE			*output;
+	unsigned long		nr_events;
+	struct strlist		*ev_qualifier;
+	struct {
+		size_t		nr;
+		int		*entries;
+	}			ev_qualifier_ids;
+	struct intlist		*tid_list;
+	struct intlist		*pid_list;
+	struct {
+		size_t		nr;
+		pid_t		*entries;
+	}			filter_pids;
+	double			duration_filter;
+	double			runtime_ms;
+	struct {
+		u64		vfs_getname,
+				proc_getname;
+	} stats;
+	bool			not_ev_qualifier;
+	bool			live;
+	bool			full_time;
+	bool			sched;
+	bool			multiple_threads;
+	bool			summary;
+	bool			summary_only;
+	bool			show_comm;
+	bool			show_tool_stats;
+	bool			trace_syscalls;
+	bool			force;
+	bool			vfs_getname;
+	int			trace_pgfaults;
+};
 
 struct tp_field {
 	int offset;
@@ -1073,6 +1125,7 @@ static size_t syscall_arg__scnprintf_getrandom_flags(char *bf, size_t size,
 	  .arg_scnprintf = { [arg] = SCA_STRARRAY, }, \
 	  .arg_parm	 = { [arg] = &strarray__##array, }
 
+#include "trace/beauty/pid.c"
 #include "trace/beauty/sched_policy.c"
 #include "trace/beauty/waitid_options.c"
 
@@ -1167,6 +1220,7 @@ static struct syscall_fmt {
 	  .arg_scnprintf = { [0] = SCA_FD, /* fd */ }, },
 	{ .name	    = "getitimer",  .errmsg = true, STRARRAY(0, which, itimers), },
 	{ .name	    = "getpid",	    .errpid = true, },
+	{ .name	    = "getpgid",    .errpid = true, },
 	{ .name	    = "getppid",    .errpid = true, },
 	{ .name	    = "getrandom",  .errmsg = true,
 	  .arg_scnprintf = { [2] = SCA_GETRANDOM_FLAGS, /* flags */ }, },
@@ -1328,6 +1382,7 @@ static struct syscall_fmt {
 			     [3] = SCA_MSG_FLAGS, /* flags */ }, },
 	{ .name	    = "set_tid_address", .errpid = true, },
 	{ .name	    = "setitimer",  .errmsg = true, STRARRAY(0, which, itimers), },
+	{ .name	    = "setpgid",    .errmsg = true, },
 	{ .name	    = "setrlimit",  .errmsg = true, STRARRAY(0, resource, rlimit_resources), },
 	{ .name	    = "setxattr",   .errmsg = true,
 	  .arg_scnprintf = { [0] = SCA_FILENAME, /* pathname */ }, },
@@ -1485,59 +1540,6 @@ fail:
 
 static const size_t trace__entry_str_size = 2048;
 
-struct trace {
-	struct perf_tool	tool;
-	struct {
-		int		machine;
-		int		open_id;
-	}			audit;
-	struct {
-		int		max;
-		struct syscall  *table;
-		struct {
-			struct perf_evsel *sys_enter,
-					  *sys_exit;
-		}		events;
-	} syscalls;
-	struct record_opts	opts;
-	struct perf_evlist	*evlist;
-	struct machine		*host;
-	struct thread		*current;
-	u64			base_time;
-	FILE			*output;
-	unsigned long		nr_events;
-	struct strlist		*ev_qualifier;
-	struct {
-		size_t		nr;
-		int		*entries;
-	}			ev_qualifier_ids;
-	struct intlist		*tid_list;
-	struct intlist		*pid_list;
-	struct {
-		size_t		nr;
-		pid_t		*entries;
-	}			filter_pids;
-	double			duration_filter;
-	double			runtime_ms;
-	struct {
-		u64		vfs_getname,
-				proc_getname;
-	} stats;
-	bool			not_ev_qualifier;
-	bool			live;
-	bool			full_time;
-	bool			sched;
-	bool			multiple_threads;
-	bool			summary;
-	bool			summary_only;
-	bool			show_comm;
-	bool			show_tool_stats;
-	bool			trace_syscalls;
-	bool			force;
-	bool			vfs_getname;
-	int			trace_pgfaults;
-};
-
 static int trace__set_fd_pathname(struct thread *thread, int fd, const char *pathname)
 {
 	struct thread_trace *ttrace = thread__priv(thread);
@@ -1763,6 +1765,8 @@ static int syscall__set_arg_fmts(struct syscall *sc)
 			sc->arg_scnprintf[idx] = sc->fmt->arg_scnprintf[idx];
 		else if (field->flags & FIELD_IS_POINTER)
 			sc->arg_scnprintf[idx] = syscall_arg__scnprintf_hex;
+		else if (strcmp(field->type, "pid_t") == 0)
+			sc->arg_scnprintf[idx] = SCA_PID;
 		++idx;
 	}
 

tools/perf/trace/beauty/pid.c

@@ -0,0 +1,18 @@
+static size_t syscall_arg__scnprintf_pid(char *bf, size_t size, struct syscall_arg *arg)
+{
+	int pid = arg->val;
+	struct trace *trace = arg->trace;
+	size_t printed = scnprintf(bf, size, "%d", pid);
+	struct thread *thread = machine__find_thread(trace->host, pid, pid);
+
+	if (thread != NULL) {
+		if (thread->comm_set)
+			printed += scnprintf(bf + printed, size - printed,
+					     " (%s)", thread__comm_str(thread));
+		thread__put(thread);
+	}
+
+	return printed;
+}
+
+#define SCA_PID syscall_arg__scnprintf_pid