[PATCH] perf tools: Emit clearer message for sys_perf_event_open ENOENT return

[David Ahern <daahern@cisco.com>]

Resend of patch sent back in January 2011 in light of recent confusion around
unsupported events for a given platform.

Improve sys_perf_event_open ENOENT return handling in top and record, just
like 5a3446b does for stat.

Retry of Arnaldo's patch using ui_warning instead of die which allows the
fallback from hardware cycles to software clock.

Signed-off-by: David Ahern <daahern@cisco.com>
---
 tools/perf/builtin-record.c |    7 +++++++
 tools/perf/builtin-top.c    |    8 ++++++++
 2 files changed, 15 insertions(+), 0 deletions(-)

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 6febcc1..cac275e 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -282,6 +282,9 @@ try_again:
 			else if (err ==  ENODEV && cpu_list) {
 				die("No such device - did you specify"
 					" an out-of-range profile CPU?\n");
+			} else if (err ==  ENOENT) {
+				ui__warning("%s event is not supported.\n",
+					    event_name(pos));
 			} else if (err == EINVAL && sample_id_all_avail) {
 				/*
 				 * Old kernel, no attr->sample_id_type_all field
@@ -307,6 +310,10 @@ try_again:
 				attr->config = PERF_COUNT_SW_CPU_CLOCK;
 				goto try_again;
 			}
+
+			if (err == ENOENT)
+				exit(1);
+
 			printf("\n");
 			error("sys_perf_event_open() syscall returned with %d (%s).  /bin/dmesg may provide additional information.\n",
 			      err, strerror(err));
diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
index 80c9e06..109e1a0 100644
--- a/tools/perf/builtin-top.c
+++ b/tools/perf/builtin-top.c
@@ -852,6 +852,10 @@ try_again:
 				die("Permission error - are you root?\n"
 					"\t Consider tweaking"
 					" /proc/sys/kernel/perf_event_paranoid.\n");
+			else if (err == ENOENT)
+				ui__warning("%s event is not supported.\n",
+					    event_name(counter));
+
 			/*
 			 * If it's cycles then fall back to hrtimer
 			 * based cpu-clock-tick sw counter, which
@@ -867,6 +871,10 @@ try_again:
 				attr->config = PERF_COUNT_SW_CPU_CLOCK;
 				goto try_again;
 			}
+
+			if (err == ENOENT)
+				exit(1);
+
 			printf("\n");
 			error("sys_perf_event_open() syscall returned with %d "
 			      "(%s).  /bin/dmesg may provide additional information.\n",
-- 
1.7.4