perf evlist: Fix grouping of multiple events

The __perf_evsel__open routing was grouping just the threads for that
specific events per cpu when we want to group all threads in all events
to the first fd opened on that cpu.

So pass the xyarray with the first event, where the other events will be
able to get that first per cpu fd.

At some point top and record will switch to using perf_evlist__open that
takes care of this detail and probably will also handle the fallback
from hw to soft counters, etc.

Reported-by: Deng-Cheng Zhu <dczhu@mips.com>
Tested-by: Deng-Cheng Zhu <dczhu@mips.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-ebm34rh098i9y9v4cytfdp0x@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 9 insertions, 2 deletions

diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
index 7a871714d44e..d2fc7542e826 100644
--- a/tools/perf/builtin-top.c
+++ b/tools/perf/builtin-top.c
@@ -834,10 +834,16 @@ static void perf_session__mmap_read(struct perf_session *self)
 
 static void start_counters(struct perf_evlist *evlist)
 {
-        struct perf_evsel *counter;
+        struct perf_evsel *counter, *first;
+
+        first = list_entry(evlist->entries.next, struct perf_evsel, node);
 
         list_for_each_entry(counter, &evlist->entries, node) {
                 struct perf_event_attr *attr = &counter->attr;
+                struct xyarray *group_fd = NULL;
+
+                if (group && counter != first)
+                        group_fd = first->fd;
 
                 attr->sample_type = PERF_SAMPLE_IP | PERF_SAMPLE_TID;
 
@@ -860,7 +866,8 @@ static void start_counters(struct perf_evlist *evlist)
                 attr->inherit = inherit;
 try_again:
                 if (perf_evsel__open(counter, top.evlist->cpus,
-                                     top.evlist->threads, group) < 0) {
+                                     top.evlist->threads, group,
+                                     group_fd) < 0) {
                         int err = errno;
 
                         if (err == EPERM || err == EACCES) {