On hybrid platform, user may want to enable the hardware event
only on one PMU. So following syntax is supported:

cpu_core/<hardware event>/
cpu_atom/<hardware event>/

  # perf stat -e cpu_core/cpu-cycles/ -a -- sleep 1

   Performance counter stats for 'system wide':

           6,049,336      cpu_core/cpu-cycles/

         1.003577042 seconds time elapsed

It enables the event 'cpu-cycles' only on cpu_core pmu.

But for 'cycles' and 'branches', the syntax doesn't work.

Before:

  # perf stat -e cpu_core/cycles/ -a -- sleep 1
  event syntax error: 'cpu_core/cycles/'
                                \___ unknown term 'cycles' for pmu 'cpu_core'

  # perf stat -e cpu_core/branches/ -a -- sleep 1
  event syntax error: 'cpu_core/branches/'
                                \___ unknown term 'branches' for pmu 'cpu_core'

For 'cpu-cycles', why it works is because the event is defined in
/sys/devices/cpu_core/events/. It's added as alias by
pmu_add_sys_aliases and it's treated as 'event' when parsing the
term->config.

We use a similar idea, create a pme_hybrid_fixup table for
'cycles' and 'branches' and add them as aliases.

After:

  # perf stat -e cpu_core/cycles/ -a -- sleep 1

   Performance counter stats for 'system wide':

           5,769,631      cpu_core/cycles/

         1.003833235 seconds time elapsed

  # perf stat -e cpu_core/branches/ -a -- sleep 1

   Performance counter stats for 'system wide':

             490,951      cpu_core/branches/

         1.003693946 seconds time elapsed

Signed-off-by: Jin Yao <yao....@linux.intel.com>
---
v3:
 - New patch in v3.

 tools/perf/util/pmu.c | 32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
index beff29981101..72e5ae5e868e 100644
--- a/tools/perf/util/pmu.c
+++ b/tools/perf/util/pmu.c
@@ -916,6 +916,35 @@ static int pmu_max_precise(const char *name)
        return max_precise;
 }
 
+static void perf_pmu__add_hybrid_aliases(struct list_head *head)
+{
+       static struct pmu_event pme_hybrid_fixup[] = {
+               {
+                       .name = "cycles",
+                       .event = "event=0x3c",
+               },
+               {
+                       .name = "branches",
+                       .event = "event=0xc4",
+               },
+               {
+                       .name = 0,
+                       .event = 0,
+               },
+       };
+       int i = 0;
+
+       while (1) {
+               struct pmu_event *pe = &pme_hybrid_fixup[i++];
+
+               if (!pe->name)
+                       break;
+
+               __perf_pmu__new_alias(head, NULL, (char *)pe->name, NULL,
+                                     (char *)pe->event, NULL);
+       }
+}
+
 static struct perf_pmu *pmu_lookup(const char *name)
 {
        struct perf_pmu *pmu;
@@ -955,6 +984,9 @@ static struct perf_pmu *pmu_lookup(const char *name)
        pmu_add_cpu_aliases(&aliases, pmu);
        pmu_add_sys_aliases(&aliases, pmu);
 
+       if (pmu->is_hybrid)
+               perf_pmu__add_hybrid_aliases(&aliases);
+
        INIT_LIST_HEAD(&pmu->format);
        INIT_LIST_HEAD(&pmu->aliases);
        INIT_LIST_HEAD(&pmu->caps);
-- 
2.17.1

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