perf trace: Infrastructure to show COMM strings for syscalls returning PIDs

Starting with clone, waitid and wait4:

  # trace -e waitid,wait4
     1.385 ( 1.385 ms): bash/12122 wait4(upid: -1, stat_addr: 0x7ffe0cee1720, options: UNTRACED|CONTINUED) = 1210 (ls)
     1.426 ( 0.002 ms): bash/12122 wait4(upid: -1, stat_addr: 0x7ffe0cee1150, options: NOHANG|UNTRACED|CONTINUED) = 0
     3.293 ( 0.604 ms): bash/1211 wait4(upid: -1, stat_addr: 0x7ffe0cee0560                             ) = 1214 (sed)
     3.342 ( 0.002 ms): bash/1211 wait4(upid: -1, stat_addr: 0x7ffe0cee01d0, options: NOHANG            ) = -1 ECHILD No child processes
     3.576 ( 0.016 ms): bash/12122 wait4(upid: -1, stat_addr: 0x7ffe0cee0550, options: NOHANG|UNTRACED|CONTINUED) = 1211 (bash)
  ^C# trace -e clone
     0.027 ( 0.000 ms): systemd/1  ... [continued]: clone()) = 1227 (systemd)
     0.050 ( 0.000 ms): systemd/1227  ... [continued]: clone()) = 0
  ^C[root@jouet ~]#

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-lyf5d3y5j15wikjb6pe6ukoi@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 9a6c7b1..22a4901 100644 (file)
--- a/tools/perf/builtin-trace.c
+++ b/tools/perf/builtin-trace.c
@@ -1082,6 +1082,7 @@ static struct syscall_fmt {
        size_t     (*arg_scnprintf[6])(char *bf, size_t size, struct syscall_arg *arg);
        void       *arg_parm[6];
        bool       errmsg;
+       bool       errpid;
        bool       timeout;
        bool       hexret;
 } syscall_fmts[] = {
@@ -1099,6 +1100,7 @@ static struct syscall_fmt {
        { .name     = "chroot",     .errmsg = true,
          .arg_scnprintf = { [0] = SCA_FILENAME, /* filename */ }, },
        { .name     = "clock_gettime",  .errmsg = true, STRARRAY(0, clk_id, clockid), },
+       { .name     = "clone",      .errpid = true, },
        { .name     = "close",      .errmsg = true,
          .arg_scnprintf = { [0] = SCA_CLOSE_FD, /* fd */ }, },
        { .name     = "connect",    .errmsg = true, },
@@ -1365,9 +1367,9 @@ static struct syscall_fmt {
          .arg_scnprintf = { [0] = SCA_FILENAME, /* filename */ }, },
        { .name     = "vmsplice",  .errmsg = true,
          .arg_scnprintf = { [0] = SCA_FD, /* fd */ }, },
-       { .name     = "wait4",      .errmsg = true,
+       { .name     = "wait4",      .errpid = true,
          .arg_scnprintf = { [2] = SCA_WAITID_OPTIONS, /* options */ }, },
-       { .name     = "waitid",     .errmsg = true,
+       { .name     = "waitid",     .errpid = true,
          .arg_scnprintf = { [3] = SCA_WAITID_OPTIONS, /* options */ }, },
        { .name     = "write",      .errmsg = true,
          .arg_scnprintf = { [0] = SCA_FD, /* fd */ }, },
@@ -2156,7 +2158,7 @@ static int trace__sys_exit(struct trace *trace, struct perf_evsel *evsel,
        if (sc->fmt == NULL) {
 signed_print:
                fprintf(trace->output, ") = %ld", ret);
-       } else if (ret < 0 && sc->fmt->errmsg) {
+       } else if (ret < 0 && (sc->fmt->errmsg || sc->fmt->errpid)) {
                char bf[STRERR_BUFSIZE];
                const char *emsg = strerror_r(-ret, bf, sizeof(bf)),
                           *e = audit_errno_to_name(-ret);
@@ -2166,7 +2168,16 @@ signed_print:
                fprintf(trace->output, ") = 0 Timeout");
        else if (sc->fmt->hexret)
                fprintf(trace->output, ") = %#lx", ret);
-       else
+       else if (sc->fmt->errpid) {
+               struct thread *child = machine__find_thread(trace->host, ret, ret);
+
+               if (child != NULL) {
+                       fprintf(trace->output, ") = %ld", ret);
+                       if (child->comm_set)
+                               fprintf(trace->output, " (%s)", thread__comm_str(child));
+                       thread__put(child);
+               }
+       } else
                goto signed_print;
 
        fputc('\n', trace->output);