perf trace: Allow suppressing the syscall argument names

To show just the values:

Default:

# trace -e open*,close,*sleep sleep 1
openat(dfd: CWD, filename: /etc/ld.so.cache, flags: CLOEXEC ) = 3
close(fd: 3 ) = 0
openat(dfd: CWD, filename: /lib64/libc.so.6, flags: CLOEXEC ) = 3
close(fd: 3 ) = 0
openat(dfd: CWD, filename: /usr/lib/locale/locale-archive, flags: CLOEXEC) = 3
close(fd: 3 ) = 0
nanosleep(rqtp: 0x7ffc0c4ea0d0, rmtp: 0 ) = 0
close(fd: 1 ) = 0
close(fd: 2 ) = 0
#

Remove it:

# perf config trace.show_arg_names=no
# trace -e open*,close,*sleep sleep 1
openat(CWD, /etc/ld.so.cache, CLOEXEC ) = 3
close(3 ) = 0
openat(CWD, /lib64/libc.so.6, CLOEXEC ) = 3
close(3 ) = 0
openat(CWD, /usr/lib/locale/locale-archive, CLOEXEC ) = 3
close(3 ) = 0
nanosleep(0x7ffced3a8c40, 0 ) = 0
close(1 ) = 0
close(2 ) = 0
#

Cc: Adrian Hunter <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Cc: Luis Cláudio Gonçalves <[e-mail]>
Cc: Namhyung Kim <[e-mail]>
Cc: Wang Nan <[e-mail]>
Link: https://lkml.kernel.org/n/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/Documentation/perf-config.txt

···
 	trace.no_inherit::
 		Do not follow children threads.
 
+	trace.show_arg_names::
+		Should syscall argument names be printed? If not then trace.show_zeros
+		will be set.
+
 	trace.show_duration::
 		Show syscall duration.
 

tools/perf/builtin-trace.c

···
 	bool			show_tstamp;
 	bool			show_duration;
 	bool			show_zeros;
+	bool			show_arg_names;
 	bool			force;
 	bool			vfs_getname;
 	int			trace_pgfaults;
···
 			      sc->arg_fmt[arg.idx].parm))
 				continue;
 
-			printed += scnprintf(bf + printed, size - printed,
-					     "%s%s: ", printed ? ", " : "", field->name);
+			printed += scnprintf(bf + printed, size - printed, "%s", printed ? ", " : "");
+
+			if (trace->show_arg_names)
+				printed += scnprintf(bf + printed, size - printed, "%s: ", field->name);
+
 			printed += syscall__scnprintf_val(sc, bf + printed, size - printed, &arg, val);
 		}
 	} else if (IS_ERR(sc->tp_format)) {
···
 		trace->show_tstamp = perf_config_bool(var, value);
 	} else if (!strcmp(var, "trace.show_duration")) {
 		trace->show_duration = perf_config_bool(var, value);
+	} else if (!strcmp(var, "trace.show_arg_names")) {
+		trace->show_arg_names = perf_config_bool(var, value);
+		if (!trace->show_arg_names)
+			trace->show_zeros = true;
 	} else if (!strcmp(var, "trace.show_zeros")) {
-		trace->show_zeros = perf_config_bool(var, value);
+		bool new_show_zeros = perf_config_bool(var, value);
+		if (!trace->show_arg_names && !new_show_zeros) {
+			pr_warning("trace.show_zeros has to be set when trace.show_arg_names=no\n");
+			goto out;
+		}
+		trace->show_zeros = new_show_zeros;
 	} else if (!strcmp(var, "trace.no_inherit")) {
 		trace->opts.no_inherit = perf_config_bool(var, value);
 	}
-
+out:
 	return err;
 }
 
···
 		.show_comm = true,
 		.show_tstamp = true,
 		.show_duration = true,
+		.show_arg_names = true,
 		.trace_syscalls = false,
 		.kernel_syscallchains = false,
 		.max_stack = UINT_MAX,