perf trace: Allow suppressing the syscall argument names

Commit-ID:  9d6dc178f0c9e40e61f45d2ac86baa8ad77cb052
Gitweb:     https://git.kernel.org/tip/9d6dc178f0c9e40e61f45d2ac86baa8ad77cb052
Author:     Arnaldo Carvalho de Melo <[email protected]>
AuthorDate: Fri, 14 Dec 2018 11:32:02 -0300
Committer:  Arnaldo Carvalho de Melo <[email protected]>
CommitDate: Tue, 18 Dec 2018 12:24:01 -0300

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
  #

---
 tools/perf/Documentation/perf-config.txt |  4 ++++
 tools/perf/builtin-trace.c               | 22 ++++++++++++++++++----
 2 files changed, 22 insertions(+), 4 deletions(-)

index ecd1e9514925..35108fd61fa6 100644
@@ -532,6 +532,10 @@ trace.*::
 	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.
 

index e978ce034863..95dfcb851604 100644
@@ -130,6 +130,7 @@ struct trace {
 	bool			show_tstamp;
 	bool			show_duration;
 	bool			show_zeros;
+	bool			show_arg_names;
 	bool			force;
 	bool			vfs_getname;
 	int			trace_pgfaults;

@@ -1613,8 +1614,11 @@ static size_t syscall__scnprintf_args(struct syscall *sc, char *bf, size_t size,
 			      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)) {

@@ -3546,12 +3550,21 @@ static int trace__config(const char *var, const char *value, void *arg)
 		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;
 }
 

@@ -3582,6 +3595,7 @@ int cmd_trace(int argc, const char **argv)
 		.show_comm = true,
 		.show_tstamp = true,
 		.show_duration = true,
+		.show_arg_names = true,
 		.trace_syscalls = false,
 		.kernel_syscallchains = false,
 		.max_stack = UINT_MAX,