perf tools: Show better error message in case we fail to open counters due to EBUSY...

Showing better error message in case we fail to open counters due to the
EBUSY error. If we detect oprofile daemon process running, we now
display following message for EBUSY error:

  $ perf record ls
  Error:
  The PMU counters are busy/taken by another profiler.
  We found oprofile daemon running, please stop it and try again.

In case oprofiled was not detected the current error message stays:

  $ perf record ls
  Error:
  The sys_perf_event_open() syscall returned with 16 (Device or resource busy) for event (cycles).
  /bin/dmesg may provide additional information.
  No CONFIG_PERF_EVENTS=y kernel support configured?

Also changing PERF_FLAG_FD_CLOEXEC detection code not to display error
in case of EBUSY error, as it currently does:

  $ perf record ls
  Error:
  perf_event_open(..., PERF_FLAG_FD_CLOEXEC) failed with unexpected error 16 (Device or resource busy)
  perf_event_open(..., 0) failed unexpectedly with error 16 (Device or resource busy)
  The PMU counters are busy/taken by another profiler.
  We found oprofile daemon running, please stop it and try again.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: William Cohen <wcohen@redhat.com>
Cc: Yann Droneaud <ydroneaud@opteya.com>
Link: http://lkml.kernel.org/r/1406908014-8312-1-git-send-email-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/util/cloexec.c b/tools/perf/util/cloexec.c
index c5d05ec172206d6d86dd1bdc14edfa29a2d7bd0f..dede0c388ed4b24edc16d4c0936626bf61098bd5 100644 (file)
--- a/tools/perf/util/cloexec.c
+++ b/tools/perf/util/cloexec.c
@@ -25,7 +25,7 @@ static int perf_flag_probe(void)
                return 1;
        }
 
-       WARN_ONCE(err != EINVAL,
+       WARN_ONCE(err != EINVAL && err != EBUSY,
                  "perf_event_open(..., PERF_FLAG_FD_CLOEXEC) failed with unexpected error %d (%s)\n",
                  err, strerror(err));
 
@@ -33,7 +33,7 @@ static int perf_flag_probe(void)
        fd = sys_perf_event_open(&attr, 0, -1, -1, 0);
        err = errno;
 
-       if (WARN_ONCE(fd < 0,
+       if (WARN_ONCE(fd < 0 && err != EBUSY,
                      "perf_event_open(..., 0) failed unexpectedly with error %d (%s)\n",
                      err, strerror(err)))
                return -1;

diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index 92e5235f537763e5fa215c6f8c7ace0dfffe47cd..0c8919decac8d591f426e8a007aa248e53f1706d 100644 (file)
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -2039,6 +2039,12 @@ int perf_evsel__open_strerror(struct perf_evsel *evsel, struct target *target,
        "No APIC? If so then you can boot the kernel with the \"lapic\" boot parameter to force-enable it.");
 #endif
                break;
+       case EBUSY:
+               if (find_process("oprofiled"))
+                       return scnprintf(msg, size,
+       "The PMU counters are busy/taken by another profiler.\n"
+       "We found oprofile daemon running, please stop it and try again.");
+               break;
        default:
                break;
        }

diff --git a/tools/perf/util/util.c b/tools/perf/util/util.c
index e52e7461911b978838e868b92f024aa642c2bf53..b82a93cb1694d08742301b6a71de016da0456ef6 100644 (file)
--- a/tools/perf/util/util.c
+++ b/tools/perf/util/util.c
@@ -536,3 +536,39 @@ void mem_bswap_64(void *src, int byte_size)
                ++m;
        }
 }
+
+bool find_process(const char *name)
+{
+       size_t len = strlen(name);
+       DIR *dir;
+       struct dirent *d;
+       int ret = -1;
+
+       dir = opendir(procfs__mountpoint());
+       if (!dir)
+               return -1;
+
+       /* Walk through the directory. */
+       while (ret && (d = readdir(dir)) != NULL) {
+               char path[PATH_MAX];
+               char *data;
+               size_t size;
+
+               if ((d->d_type != DT_DIR) ||
+                    !strcmp(".", d->d_name) ||
+                    !strcmp("..", d->d_name))
+                       continue;
+
+               scnprintf(path, sizeof(path), "%s/%s/comm",
+                         procfs__mountpoint(), d->d_name);
+
+               if (filename__read_str(path, &data, &size))
+                       continue;
+
+               ret = strncmp(name, data, len);
+               free(data);
+       }
+
+       closedir(dir);
+       return ret ? false : true;
+}

diff --git a/tools/perf/util/util.h b/tools/perf/util/util.h
index 38af77550c755a1f901ce42fb16891e45a303378..03a1ea2266b874b831dbf208c66af7ead0d2d179 100644 (file)
--- a/tools/perf/util/util.h
+++ b/tools/perf/util/util.h
@@ -346,4 +346,5 @@ void mem_bswap_64(void *src, int byte_size);
 void mem_bswap_32(void *src, int byte_size);
 
 const char *get_filename_for_perf_kvm(void);
+bool find_process(const char *name);
 #endif /* GIT_COMPAT_UTIL_H */