[PATCH RESEND 1/2] perf evlist: Return first evsel for non-sample event on old kernel

[PATCH RESEND 1/2] perf evlist: Return first evsel for non-sample event on old kernel

[Namhyung Kim]

On old kernels that don't support sample_id_all feature,
perf_evlist__id2evsel() returns NULL for non-sampling events.
This breaks perf top when multiple events are given on command
line. Fix it by using first evsel in the evlist. This will also
prevent getting the same (potential) problem in such new tool/
old kernel combo.

Suggested-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: Namhyung Kim <namhyung.kim@lge.com>
---
 tools/perf/util/evlist.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index 5c61dc57d7c7..f8da9fada002 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -349,6 +349,10 @@ struct perf_evsel *perf_evlist__id2evsel(struct perf_evlist *evlist, u64 id)
 	hlist_for_each_entry(sid, pos, head, node)
 		if (sid->id == id)
 			return sid->evsel;
+
+	if (!perf_evlist__sample_id_all(evlist))
+		return list_entry(evlist->entries.next, struct perf_evsel, node);
+
 	return NULL;
 }
 
-- 
1.7.9

[PATCH RESEND 2/2] perf tools: Add error message for EMFILE

[Namhyung Kim]

When a user tries to open so many event on multiple tasks/cpus,
perf_event_open syscall may fail with EMFILE. Provide an advice
for that case.

Signed-off-by: Namhyung Kim <namhyung.kim@lge.com>
Cc: David Ahern <dsahern@gmail.com>
---
 tools/perf/builtin-record.c |    5 +++++
 tools/perf/builtin-stat.c   |    4 ++++
 tools/perf/builtin-top.c    |    3 ++-
 3 files changed, 11 insertions(+), 1 deletions(-)

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 75d230fef202..b1112084a0ae 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -260,6 +260,11 @@ try_again:
 				ui__warning("The %s event is not supported.\n",
 					    event_name(pos));
 				exit(EXIT_FAILURE);
+			} else if (err == EMFILE) {
+				ui__warning("Too many events are opened.\n"
+					    "Try again after reducing the number of events,\n"
+					    "tasks and/or cpus.\n");
+				exit(EXIT_FAILURE);
 			}
 
 			printf("\n");
diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index ea40e4e8b227..e54cbc9fc4fd 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -477,6 +477,10 @@ static int run_perf_stat(int argc __used, const char **argv)
 				      "\t Consider tweaking"
 				      " /proc/sys/kernel/perf_event_paranoid or running as root.",
 				      system_wide ? "system-wide " : "");
+			} else if (errno == EMFILE) {
+				error("Too many events are opened.\n"
+				      "\t Try again after reducing the number of events,\n"
+				      "\t tasks and/or cpus.");
 			} else {
 				error("open_counter returned with %d (%s). "
 				      "/bin/dmesg may provide additional information.\n",
diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
index e3c63aef8efc..d0d05943fade 100644
--- a/tools/perf/builtin-top.c
+++ b/tools/perf/builtin-top.c
@@ -923,7 +923,8 @@ try_again:
 				goto out_err;
 			} else if (err == EMFILE) {
 				ui__warning("Too many events are opened.\n"
-					    "Try again after reducing the number of events\n");
+					    "Try again after reducing the number of events,\n"
+					    "tasks and/or cpus.\n");
 				goto out_err;
 			}
 
-- 
1.7.9

Re: [PATCH RESEND 1/2] perf evlist: Return first evsel for non-sample event on old kernel

[Namhyung Kim]

Ping. :)


2012-02-20 10:47 AM, Namhyung Kim wrote:
> On old kernels that don't support sample_id_all feature,
> perf_evlist__id2evsel() returns NULL for non-sampling events.
> This breaks perf top when multiple events are given on command
> line. Fix it by using first evsel in the evlist. This will also
> prevent getting the same (potential) problem in such new tool/
> old kernel combo.
>
> Suggested-by: Arnaldo Carvalho de Melo<acme@ghostprotocols.net>
> Signed-off-by: Namhyung Kim<namhyung.kim@lge.com>
> ---
>   tools/perf/util/evlist.c |    4 ++++
>   1 files changed, 4 insertions(+), 0 deletions(-)
>
> diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
> index 5c61dc57d7c7..f8da9fada002 100644
> --- a/tools/perf/util/evlist.c
> +++ b/tools/perf/util/evlist.c
> @@ -349,6 +349,10 @@ struct perf_evsel *perf_evlist__id2evsel(struct perf_evlist *evlist, u64 id)
>   	hlist_for_each_entry(sid, pos, head, node)
>   		if (sid->id == id)
>   			return sid->evsel;
> +
> +	if (!perf_evlist__sample_id_all(evlist))
> +		return list_entry(evlist->entries.next, struct perf_evsel, node);
> +
>   	return NULL;
>   }
>

[tip:perf/urgent] perf evlist: Return first evsel for non-sample event on old kernel

[tip-bot for Namhyung Kim]

Commit-ID:  30e68bcc67e41ab6dab4e4e1efc7ea8ca893c0af
Gitweb:     http://git.kernel.org/tip/30e68bcc67e41ab6dab4e4e1efc7ea8ca893c0af
Author:     Namhyung Kim <namhyung.kim@lge.com>
AuthorDate: Mon, 20 Feb 2012 10:47:26 +0900
Committer:  Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Wed, 29 Feb 2012 18:29:44 -0300

perf evlist: Return first evsel for non-sample event on old kernel

On old kernels that don't support sample_id_all feature,
perf_evlist__id2evsel() returns NULL for non-sampling events.

This breaks perf top when multiple events are given on command line. Fix
it by using first evsel in the evlist. This will also prevent getting
the same (potential) problem in such new tool/ old kernel combo.

Suggested-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1329702447-25045-1-git-send-email-namhyung.kim@lge.com
Signed-off-by: Namhyung Kim <namhyung.kim@lge.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/util/evlist.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index 3f16e08..ea32a06 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -349,6 +349,10 @@ struct perf_evsel *perf_evlist__id2evsel(struct perf_evlist *evlist, u64 id)
 	hlist_for_each_entry(sid, pos, head, node)
 		if (sid->id == id)
 			return sid->evsel;
+
+	if (!perf_evlist__sample_id_all(evlist))
+		return list_entry(evlist->entries.next, struct perf_evsel, node);
+
 	return NULL;
 }