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

From: Namhyung Kim
Date: Wed Feb 22 2012 - 21:21:38 EST


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@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Namhyung Kim<namhyung.kim@xxxxxxx>
---
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;
}


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