Changing the way we retrieve the event ID. Instead of parsing out
the ID out of the read data, using the PERF_EVENT_IOC_ID ioctl.

Keeping the old way in place to support kernels without
PERF_EVENT_IOC_ID ioctl support.

Signed-off-by: Jiri Olsa <jo...@redhat.com>
Cc: Arnaldo Carvalho de Melo <a...@ghostprotocols.net>
Cc: Peter Zijlstra <a.p.zijls...@chello.nl>
Cc: Ingo Molnar <mi...@elte.hu>
Cc: Paul Mackerras <pau...@samba.org>
Cc: Corey Ashford <cjash...@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweis...@gmail.com>
Cc: Namhyung Kim <namhy...@kernel.org>
---
 tools/perf/util/evlist.c | 34 ++++++++++++++++++++++++----------
 1 file changed, 24 insertions(+), 10 deletions(-)

diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index 561bdfb..ef13aab 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -290,19 +290,33 @@ static int perf_evlist__id_add_fd(struct perf_evlist 
*evlist,
                                  struct perf_evsel *evsel,
                                  int cpu, int thread, int fd)
 {
-       u64 read_data[4] = { 0, };
-       int id_idx = 1; /* The first entry is the counter value */
+       u64 id;
+       int ret;
 
-       if (!(evsel->attr.read_format & PERF_FORMAT_ID) ||
-           read(fd, &read_data, sizeof(read_data)) == -1)
-               return -1;
+       ret = ioctl(fd, PERF_EVENT_IOC_ID, &id);
+       if (!ret)
+               goto add;
+
+       /* Legacy way to get event id.. All hail to old kernels! */
+       if (errno == ENOTTY) {
+               u64 read_data[4] = { 0, };
+               int id_idx = 1; /* The first entry is the counter value */
+
+               if (!(evsel->attr.read_format & PERF_FORMAT_ID) ||
+                   read(fd, &read_data, sizeof(read_data)) == -1)
+                       return -1;
 
-       if (evsel->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
-               ++id_idx;
-       if (evsel->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
-               ++id_idx;
+               if (evsel->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
+                       ++id_idx;
+               if (evsel->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
+                       ++id_idx;
+
+               id = read_data[id_idx];
+       } else if (errno)
+               return -1;
 
-       perf_evlist__id_add(evlist, evsel, cpu, thread, read_data[id_idx]);
+ add:
+       perf_evlist__id_add(evlist, evsel, cpu, thread, id);
        return 0;
 }
 
-- 
1.7.11.4

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